CN101782945B - Method for identifying loose supporting ropes based on space coordinate monitoring during support settlement - Google Patents

Abstract

The method of identifying loose support cables based on spatial coordinate monitoring when there is support settlement is based on spatial coordinate monitoring. By monitoring the structural support coordinates, it is determined whether it is necessary to update the mechanical calculation benchmark model of the structure. Only when the structural support coordinates change The mechanical calculation benchmark model of the structure is updated to obtain a new mechanical calculation benchmark model of the structure including the settlement of the structural support. Based on this model, the change matrix of the unit damage monitored quantity is calculated. According to the approximate linear relationship between the current strain vector and the initial strain vector, the virtual unit damage strain change matrix and the current virtual damage vector, the virtual damaged cable can be calculated and identified. After using the nondestructive testing method to identify the real damaged cable, the remaining The virtual damaged cable is the slack cable, that is, the cable whose force needs to be adjusted, and the cable length to be adjusted can be determined according to the relationship between the degree of relaxation and the degree of virtual damage.

Description

A Method for Identifying Slack Support Cables Based on Spatial Coordinate Monitoring in Case of Support Settlement

technical field

When there is support settlement, the present invention recognizes the cables to be adjusted in the cable system (referring to all supporting cables) of cable support structures (especially large cable structures, such as large cable-stayed bridges and suspension bridges) based on the monitoring of spatial coordinate equivalents. The supporting cable of force is given, and the specific adjustment amount of cable length is given, which belongs to the field of engineering structure safety.

Background technique

The cable system is usually a key component of cable structures (especially large cable structures, such as large cable-stayed bridges and suspension bridges). Due to relaxation and other reasons, the cable force of the supporting cables usually changes after a period of time after the completion of the new structure, and the structure has been in service for a long time. Later, the relaxation of the supporting cables will also cause changes in the cable force of the supporting cables. These changes will cause changes in the internal forces of the structure, which will have a negative impact on the safety of the structure. In severe cases, it will cause the failure of the structure. Strong support cables are very necessary.

When the health state of the supporting cable system changes (such as relaxation, damage, etc.), in addition to the change of the cable force, it will also cause changes in other measurable parameters of the structure, such as the spatial coordinates of the cable structure. The change of the upper spatial coordinates contains the health status information of the cable system, that is to say, the structural spatial coordinates can be used to judge the health status of the structure, and the monitoring can be based on the spatial coordinates (the monitored spatial coordinates are referred to as "monitored quantities" in the present invention, The "monitored quantity" mentioned later refers to the monitored spatial coordinates) to identify damaged cables. The monitored quantity is not only affected by the health status of the cable system, but also affected by the settlement of the cable structure support (which often occurs) , there is no public and effective health monitoring system and method to solve this problem. Therefore, it is possible to identify the cable whose force needs to be adjusted based on the monitoring of the monitored quantity. In this way, when there is support settlement, there must be a reasonable and effective relationship between the monitored quantity and the characteristic parameters of all cables (specifically according to the characteristic parameters of the cable). To characterize the relationship between the cable whose force needs to be adjusted), the identification result of the supporting cable whose force needs to be adjusted based on this method will be more credible.

Contents of the invention

Technical problem: The purpose of the present invention is to disclose a monitoring method based on spatial coordinate equivalents for the identification of the supporting cables in the cable system in the cable structure that need to adjust the cable force when the cable structure support has settlement. A method for identifying loose support cables based on spatial coordinate monitoring during the settlement of a support that needs to be adjusted reasonably and effectively.

Technical solution: According to the reasons for the change of the cable force of the support cable, the change of the cable force of the support cable can be divided into three situations: one is that the support cable is damaged, such as local cracks and corrosion in the support cable, etc.; the other is that the support cable is damaged. There is no damage to the cable, but the cable force has also changed. One of the main reasons for this change is the cable length (called the free length) under the free state of the supporting cable (the cable tension is also called the cable force is 0 at this time). Specifically refers to the free length of the cable between the two supporting ends of the supporting cable) has changed; the third is that the supporting cable is not damaged, but the support of the cable structure has displacement (the component in the direction of gravity is called settlement), It will also cause changes in the internal force of the structure, and of course it will also cause changes in the cable force. One of the main purposes of the present invention is to identify the supporting cables whose free length has changed when there is a support displacement, and to identify the change in their free length, which provides a basis for the cable force adjustment of the cable. direct basis. The reason for the change in the free length of the support cable is not single. For convenience, the present invention refers to the support cable whose free length changes as a slack cable.

The present invention is made up of two major parts. They are respectively: 1. A method for establishing the knowledge base and parameters required for the health monitoring system of the supporting cable for identifying the cable force that needs to be adjusted in the cable system, based on the knowledge base (including parameters), based on the actual measured cable structure support coordinates A method based on the monitoring of the monitored quantity equivalent to identify the supporting cable of the cable structure that needs to adjust the cable force. Second, the software and hardware parts of the health monitoring system.

The first part of the present invention: the method for establishing the knowledge base and parameters required for identifying the health monitoring system of the supporting cable in the cable system that needs to adjust the cable force, based on the knowledge base (including parameters), based on the actual measured cable structure support Coordinated, based on the monitoring of the monitored quantity equivalent, the method of identifying the supporting cable of the cable structure that needs to adjust the cable force. The following method can be used to obtain a more accurate assessment of the health status of the cable system.

Step 1: first establish the initial virtual damage vector d _o of the cable system (because the supporting cable may actually be slack without damage, in order to show the difference, it is called "virtual damage" hereafter), and establish the initial mechanical calculation basis of the cable structure Model A _o (eg finite element reference model, A _o is constant in the present invention).

Assuming that there are N cables in the cable system, the "initial virtual damage vector of the cable system is denoted as d _o " (as shown in formula (1)), and the cable structure is represented by d _o (denoted by the initial mechanical calculation benchmark model A _o of the cable structure ) of the health status of the cable system.

d _o ＝[d _o1 d _o2 …d _oj …d _oN ] ^T (1) In formula (1), d _oj (j=1, 2, 3, ......, N) means that in A _o The initial virtual damage value of the jth cable of the cable system. When d _oj is 0, it means that the jth cable has no damage and no slack. When it is 100%, it means that the cable completely loses its bearing capacity. The jth cable loses a corresponding proportion of its bearing capacity. In formula (1), T represents the transposition of the vector (the same below).

When establishing the initial virtual damage vector of the cable system (denoted as d _o according to formula (1), the initial virtual damage vector d _o of the cable system is established by using the non-destructive testing data of the cable and other data that can express the health status of the cable. If there is no non-destructive testing data of the cable and other data that can express the healthy state of the cable, or when the initial state of the structure can be considered as a state of no damage and no relaxation, the value of each element of the vector d _o is 0.

A method for establishing an initial mechanical calculation benchmark model A _o (such as a finite element benchmark model) and a current mechanical calculation benchmark model A ^t _o (such as a finite element benchmark model) of the cable structure. A _o is constant in the present invention. A ^t _o is constantly updated. The method of establishing A _o and A ^t _o is as follows:

According to the cable structure design drawings, as-built drawings and measured data (including cable non-destructive testing data and other data that can express the health status of the cable, cable structure shape data, structure angle data, cable force data, tie rod tension data) when the cable structure is completed Data, cable structure support coordinate data, cable structure modal data and other measured data, for cable-stayed bridges and suspension bridges are bridge type data, cable force data, bridge modal data), using mechanical methods (such as method) to establish A _o ; if there is no actual measurement data of the structure when the cable structure is completed, the actual measurement data of the cable structure (including cable structure shape data, cable force data, The actual measured data such as tie rod tension data, cable structure support coordinate data, and cable structure modal data are bridge type data, cable force data, bridge modal data, and cable nondestructive testing data for cable-stayed bridges and suspension bridges. and other data that can express the health state of the cable), according to this data and the design drawing and as-built drawing of the cable structure, use mechanical methods (such as finite element method) to establish A _o . Regardless of the method used to obtain A _o , the calculated data of the cable structure based on A _o (for cable-stayed bridges and suspension bridges, the bridge type data, cable force data, and bridge modal data) must be very close to the measured data. Data, the error is generally not greater than 5%. In this way, the strain calculation data, cable force calculation data, cable structure shape calculation data, displacement calculation data, cable structure angle data, etc. under the simulated situation obtained by A _o calculation can be reliably close to the measured data when the simulated situation actually occurs . The cable structure support coordinate data corresponding to A _o constitutes the initial cable structure support coordinate vector U _o . A _o and U _o are invariant.

"All the monitored spatial coordinate data of the structure" is described by the spatial coordinates of K specified points on the structure and L specified directions of each specified point. The change of the structural space coordinate data is all the spatial coordinates of the K specified points Changes in coordinate components. Each time there are M (M=K×L) space coordinate measured values or calculated values to represent the structural space coordinate information. K and M shall not be less than the number N of supporting cables. For the sake of convenience, the "monitored spatial coordinate data of the structure" is simply referred to as "monitored quantity" in the present invention.

In the present invention, the initial vector C _o of the monitored quantity is used to represent the vector composed of the initial values of all the monitored quantities of the cable structure (see formula (1)). It is required to obtain C _o while obtaining A _o . Because under the aforementioned conditions, the monitored quantity calculated based on the calculation reference model of the cable structure is reliably close to the measured data of the initial monitored quantity, in the following description, the calculated value and the measured value will be represented by the same symbol.

C _o ＝[C _o1 C _o2 …C _oj …C _oM ] ^T (1) In formula (1), C _oj (j=1, 2, 3, ......, M; M≥N) is The initial quantity of the jth monitored quantity in the index structure, this component corresponds to the specific jth monitored quantity according to the numbering rules. T represents the transpose of the vector (the same below).

The current value vector C of the monitored quantity used in the present invention is a vector composed of the current values of all the monitored quantities in the cable structure (see formula (2) for definition).

C=[C ₁ C ₂ ...C _j ...C _M ] ^T (2) In formula (2), C _j (j=1, 2, 3, ...., M; M≥N) is the index The current value of the jth monitored quantity in the structure, the component C _j corresponds to the same "monitored quantity" as C _oj according to the numbering rules.

Step 2: Establish the current mechanical calculation benchmark model A ^t _o of the cable structure (such as the finite element benchmark model, A ^t _o is constantly updated during the operation of the health monitoring system) and the measured support coordinate vector U ^t of the current cable structure. During the service process of the cable structure, the current data of the support coordinates of the cable structure are continuously measured (all data form the current measured support coordinate vector U ^t of the cable structure, and the definition method of the vector U ^t is the same as that of the vector U _o ). For convenience, the current data of the cable structure support coordinates when the current mechanical calculation benchmark model was updated last time is recorded as the current cable structure support coordinate vector U ^t _o . The method of establishing and updating A ^t _o is: when the health monitoring system starts working for the first time, the current mechanical calculation benchmark model A ^t _o of the cable structure is equal to A _o . During the service process of the cable structure, the coordinate data of the support of the cable structure is continuously measured to obtain the coordinate vector U ^t of the current measured support of the cable structure. If U ^t is equal to U ^t _o , there is no need to update A ^t _o ; if U ^t is not is equal to U ^t _o , then A ^t _o needs to be updated. At this time, the difference between U ^t and U _o is the support displacement of the cable structure support with respect to the initial position (corresponding to A _o ). Seat displacement, the displacement in the direction of gravity is the settlement of the support). The method to update A ^t _o is: apply the current support displacement constraint to the cable structure support in A _o , the value of the current support displacement constraint is taken from the value of the corresponding element in the current support displacement vector V, and for A _o After the current support displacement constraint is applied to the cable structure support of , the updated current mechanical calculation benchmark model A ^t _o is finally obtained. After updating A ^t _o , all element values of U ^t _o are replaced by all element values of U ^t , that is, update U ^t _o is obtained, so that U ^t _o corresponding to A ^t _o is obtained.

Step 3: Establish the “value change matrix ΔC of monitored quantity of virtual unit damage” and “nominal virtual unit damage vector D _u ”. ΔC and D _u are constantly updated, that is, while updating the current benchmark model A ^t _o , to update the virtual unit damage value change matrix ΔC and the nominal virtual unit damage vector D _u .

The process of establishing and updating the numerical change matrix ΔC of the monitored quantity of virtual unit damage and the nominal virtual unit damage vector D _u is as follows:

Several calculations are performed on the basis of the current mechanical calculation benchmark model A ^to of the cable structure, and _the number of calculations is numerically equal to the number of all cables. Each calculation assumes that there is only one cable in the cable system. On the basis of the original virtual damage (the original virtual damage can be 0 or not 0), the virtual unit damage (for example, 5%, 10%, 20% or 30% and other damages are virtual unit damages). For the convenience of calculation, when setting the virtual unit damage, the structural health status can be regarded as completely healthy, and on this basis, the virtual unit damage (calculated in the subsequent steps, the damage value of the cable--- It is called the nominal virtual damage d _c , which is relative to the healthy state of the cable as being completely healthy, so the calculated nominal virtual damage must be converted into real virtual damage according to the formula given later). The cable with virtual damage in each calculation is different from the cable with virtual damage in other calculations, and the virtual unit damage value of the cable with virtual damage can be different from the virtual unit damage value of other cables in each calculation, using "nominal The virtual unit damage vector D _u ” (shown in formula (3)) records the hypothetical virtual unit damage of all cables, denoted as D _u , each calculation uses mechanical methods (such as finite element method) to calculate the The current calculated values of the M monitored quantities specified above, the current calculated values of the M monitored quantities obtained from each calculation form a "calculated current value vector of the monitored quantities" (when it is assumed that the jth root cable has unit damage , the calculation current value vector C _tj of all specified M monitored quantities can be expressed by formula (4); the calculated current value vector of the monitored quantity obtained by each calculation subtracts the initial value vector C _o of the monitored quantity, and the obtained The vector is the "value change vector of the monitored quantity" under this condition (marked by the position or number of the cable with virtual unit damage) (when the jth cable has a virtual unit damage, use δC _j to represent the monitored quantity The value change vector of δC _j is defined in formula (5), formula (6) and formula (7), formula (5) is formula (4) minus formula (2) and then divided by the jth of vector D _u elements D _uj ), each element of the value change vector δC _j of the monitored quantity represents the virtual unit damage (such as D _uj ) of the cable (such as the jth cable) assumed to have virtual unit damage during calculation, And the rate of change of the value change of the monitored quantity corresponding to the element relative to the assumed virtual unit damage D _uj ; there are N "value change vectors of the monitored quantity" with N cables, and each monitored The numerical change vector of the quantity has M (generally, M≥N) elements, and the "monitored quantity change matrix ΔC of unit damage" with M×N elements is formed in turn by these N "value change vectors of the monitored quantity" (M rows and N columns), each vector δC _j (j=1, 2, 3, ..., N) is a column of the matrix ΔC, and the definition of ΔC is shown in formula (8).

D _u ＝[D _u1 D _u2 … _{D uj} …D _uN ] ^T (3) Element D _uj (j=1, 2, 3,  … ., N) represents the assumed virtual unit damage value of the jth cable, and the value of each element in the vector D _u can be the same or different.

C _tj ＝[C _tk1 C _tk2 ...C _tjk ...C _tjM ] ^T (4) Element C _tjk (j=1,2,3,...,N; k=1, 2, 3, ...., M; M≥N) indicates that when the jth cable has a virtual unit damage, the current value of the kth specified monitored quantity corresponding to the numbering rule is calculated.

$\mathrm{<span\; class="notranslate">\; \&delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; tj</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; uj</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

In the formula (5), the subscript j (j=1, 2, 3, ..., N) indicates that the jth cable has a virtual unit damage, where D _uj is the jth cable in the vector D _u element. The definition of vector δC _j is as shown in formula (6), the kth (k=1, 2, 3, ..., M; M≥N) element δC _jk of δC _j represents when the matrix ΔC is established , assuming that the j-th cable has a virtual unit damage, the calculated change rate of the k-th monitored quantity relative to the assumed virtual unit damage D _uj is defined as shown in formula (7).

δC _j =[δC _j1 δC _j2 ... δC _jk ... δC _jM ] ^T (6)

$\mathrm{<span\; class="notranslate">\; \&delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; jk</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; tjk</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; ok</span>}}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; uj</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

The definitions of the quantities in formula (7) have been described above.

ΔC=[δC ₁ δC ₂ ... δC _j ... δC _N ] (8) In formula (8), the vector δC _j (j=1, 2, 3, ......, N) represents that due to the jth cable The relative value change of all monitored quantities caused by the virtual unit damage D _uj . The numbering rule of the column (subscript j) of the matrix ΔC is the same as the numbering rule of the subscript j of the elements of the previous vector d _o .

During the service process of the cable structure, the current data of the support coordinates of the cable structure are continuously measured. Once it is detected that U ^t is not equal to U ^t _o , it is necessary to go back to the second step to update A ^t _o . After updating A ^t _o Then enter this step to update ΔC. In fact, ΔC is constantly updated, that is, after updating the current mechanical calculation benchmark model A ^to , update the _value change matrix ΔC of the monitored quantity of virtual unit damage.

Step 4: Identify the current health status of the cable system. The specific process is as follows.

Cable system "current (calculated or measured) numerical vector C of the monitored quantity" is the same as "initial numerical vector C _o of the monitored quantity", "virtual unit damage monitored quantity numerical change matrix ΔC" and "current nominal virtual damage vector d The approximate linear relationship between _c ” is shown in formula (9) or formula (10).

C＝C _o +ΔC d _c (9)

CC _o = ΔC d _c (10) The definition of the current (calculated or measured) numerical vector C of the monitored quantity in formula (9) and formula (10) is similar to the definition of the initial numerical vector C _o of the monitored quantity, see Equation (11); see Equation (12) for the definition of “current nominal virtual damage vector d _c ” of the cable system.

C=[C ₁ C ₂ ... C _k ... C _M ] ^T (11) The element C _k (k=1, 2, 3, ...., M; M≥N) in formula (11) is The current value of the monitored quantity with the number k corresponding to the index structure and according to the numbering rule.

d _c ＝[d _c1 d _c2 …d _cj …d _cN ] ^T (12) In formula (12), d _cj (j=1, 2, 3, ......, N) is the jth The current nominal virtual damage value of the root cable, the numbering rule of the subscript j of the element of the vector d _c is the same as the numbering rule of the column of the matrix ΔC.

When the actual damage of the cable is not too large, since the cable structure material is still in the linear elastic stage, the deformation of the cable structure is also small, and the error of such a linear relationship represented by formula (9) or formula (10) is relatively small compared with the actual situation. Small, the error can be defined by the error vector e (Equation (13)), which represents the error of the linear relationship shown in Equation (9) or Equation (10).

e=abs(ΔC·d _c -C+C _o ) (13) abs() in formula (13) is an absolute value function, and an absolute value is obtained for each element of the vector obtained within the brackets.

Since there is a certain error in the linear relationship represented by formula (9) or formula (10), it cannot be directly solved according to formula (9) or formula (10) and "the current (measured) value vector C of the monitored quantity" to obtain "Current Nominal Virtual Damage Vector d _c ". If this is done, the elements in the obtained vector _dc may even have relatively large negative values, that is, negative damage, which is obviously unreasonable. Therefore, it is a reasonable solution to obtain an acceptable solution of the vector d _c (that is, with reasonable error, but the position of the virtual damaged cable and its virtual damage degree can be determined more accurately), which can be expressed by formula (14) One method.

abs(ΔC·d _c -C+C _o )≤g (14) In formula (14), abs() is an absolute value function, and the vector g describes the deviation from the ideal linear relationship (formula (9) or formula (10)). Reasonable deviation, defined by formula (15).

g=[g ₁ g ₂ ...g _k ...g _M ] ^T (15) In formula (15), g _k (k=1, 2, 3, ......, M) describes the deviation from formula (9 ) or the maximum allowable deviation of the ideal linear relationship shown in formula (10). The vector g can be selected according to the error vector e defined by formula (13).

In the "initial numerical vector C _o of the monitored quantity" (obtained by actual measurement or calculation), "the numerical change matrix ΔC of the monitored quantity of virtual unit damage" (obtained by calculation) and "the current numerical vector C of the monitored quantity" (obtained by actual measurement) When known, an appropriate algorithm (such as a multi-objective optimization algorithm) can be used to solve equation (14) to obtain an acceptable solution of the "current nominal virtual damage vector d _c ", and then the "current actual virtual damage vector d" (defined in The elements of formula (16)) can be calculated according to formula (17), that is, the "current actual virtual damage vector d" is obtained, so that the position of the virtual damaged cable and the degree of virtual damage can be determined by d, and then according to the following description The method determines the position and degree of slack of the slack cable, that is, determines the cable whose force needs to be adjusted and its length adjustment.

d=[d ₁ d ₂ ...d _j ...d _N ] ^T (16) In formula (16), d _j (j=1, 2, 3, ......, N) represents the The actual virtual damage value is defined in formula (17). When _dj is 0, it means that the jth cable has no damage and no slack; when it is 100%, it means that the cable completely loses its bearing capacity; The jth cable loses the bearing capacity of the corresponding proportion, and the numbering rule of the elements of the vector d is the same as that of the elements of the vector d _o in formula (1).

d _j =1-(1-d _oj )(1-d _cj ) (17) In formula (17), d _oj (j=1, 2, 3,..., N) is the vector d _o The jth element of d _cj is the jth element of the vector d _c .

The following describes how to determine the position and slack degree of the slack cable after the current actual virtual damage vector d of the cable is obtained.

Assuming that there are N supporting cables in the cable system, the structural cable force data is described by the cable forces of N supporting cables. The "initial cable force vector F _o " can be used to represent the initial cable force of all supporting cables in the cable structure (see formula (18) for definition). Because the initial cable force calculated based on the calculation benchmark model of the cable structure is reliably close to the measured data of the initial cable force, in the following description, the calculated value and the measured value will be represented by the same symbol.

F _o ＝[F _o1 F _o2 …F _oj …F _oN ] ^T (18) In formula (18), F _o (j=1, 2, 3, ......, N) is the first The initial cable force of j supporting cables, this element corresponds to the cable force of the specified supporting cable according to the numbering rules. Vector F _o is constant. The vector F _o is used when establishing the benchmark model A _o for the initial mechanical calculation of the cable structure.

In the present invention, "current cable force vector F" is used to represent the measured current cable force of all supporting cables in the cable structure (see formula (19) for definition).

F=[F ₁ F ₂ ...F _j ...F _N ] ^T (19) In formula (19), F _j (j=1, 2, 3,..., N) is the jth The current cable force of the root support cable.

In the present invention, under the initial state of the support cable (no damage, no slack), and the support cable is in a free state (free state means that the cable force is 0, the same hereinafter), the length of the support cable is called the initial free length, and is expressed by " The initial free length vector l _o ” represents the initial free length of all supporting cables in the cable structure (see formula (20) for definition).

l _o ＝[l _o1 l _o2 …l _oj …l _oN ] ^T (20) In formula (20), l _oj (j=1, 2, 3, ......, N) is the first The initial free length of j supporting cables. The vector l _o is a constant, and it will not change after it is determined at the beginning.

In the present invention, "current free length vector l" is used to represent the current free lengths of all supporting cables in the cable structure (see formula (21) for definition).

l=[l ₁ l ₂ …l _j …l _N ] ^T (21) In formula (21), l _j (j=1, 2, 3, ......, N) is the jth in the cable structure The current free length of the root support cable.

In the present invention, the "free length change vector Δl" (or the current slackness vector of the support cables) is used to represent the changes in the free lengths of all the support cables in the cable structure (see formula (22) and formula (23) for definitions).

Δl=[Δl ₁ Δl ₂ ... Δl _j ... Δl _N ] ^T (22) In formula (22), Δl _j (j=1, 2, 3, ......, N) is the first The change of the free length of the j supporting cables is defined in formula (23). The cable whose Δl _j is not 0 is a slack cable, and the value of Δl _j is the slack of the cable, and represents the The current slack degree is also the cable length adjustment amount of the cable when the cable force is adjusted.

Δl _j =l _j -l _oj (23)

In the present invention, the degree of relaxation of the slack cable is identified by mechanically equivalent the slack cable to the damaged cable, and the equivalent mechanical condition is:

1. The initial free length, geometric characteristic parameters and material mechanical characteristic parameters of the two equivalent cables are the same when there is no relaxation and no damage;

2. After relaxation or damage, the cable force and the total length after deformation of the two equivalent slack cables and damaged cables are the same.

When the above two equivalent conditions are met, the mechanical functions of such two supporting cables in the structure are exactly the same, that is, if the equivalent damaged cable is used to replace the slack cable, the cable structure will not change, and vice versa. Of course.

In the present invention, the current actual virtual damage degree of the virtual damaged support cable equivalent to the jth support cable (its current degree of relaxation is defined by Δl _j ) is represented by d _j (see formula (16) for the definition of d _j and formula (17)). The relationship between the current slack degree Δl _j (the definition of Δl _j is shown in formula (22)) of the j-th supporting cable and the current actual virtual damage degree d _j of the equivalent damaged cable is determined by the above two mechanical equivalent conditions Sure. The specific relationship between Δl _j and d _j can be realized by various methods, for example, it can be directly determined according to the aforementioned equivalent conditions (see formula (24)), or it can be based on the Ernst equivalent elastic modulus instead of formula (24) E is determined after correction (see formula (25)), and can also be determined by other methods such as trial algorithm based on finite element method.

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}\frac{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}{\mathrm{<span\; class="notranslate">\; EA</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; oj</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; twenty\; four</span>}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}\frac{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{<span\; class="notranslate">\; [</span>\frac{\mathrm{<span\; class="notranslate">\; E.</span>}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; ix</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; AE</span>}}{\mathrm{<span\; class="notranslate">\; 12</span>}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 3</span>}}}}<span\; class="notranslate">\; ]</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; oi</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 25</span>}<span\; class="notranslate">\; )</span>$

In formula (24) and formula (25), E is the elastic modulus of the support cable, A is the cross-sectional area of the support cable, F _j is the current cable force of the support cable, d _j is the current actual force of the support cable virtual damage degree, ω is the weight per unit length of the supporting cable, and _ljx is the horizontal distance between the two supporting ends of the supporting cable. The term in [] in formula (25) is the Ernst equivalent elastic modulus of the support cable, and the current relaxation degree vector Δl of the support cable can be determined from formula (24) or formula (25). Equation (25) is a modification of Equation (24).

The second part of the present invention: the software and hardware parts of the health monitoring system. The hardware part includes the monitoring system (monitoring the monitored quantity, monitoring the coordinates of the cable structure support, monitoring the cable force, and monitoring the horizontal distance between the two supporting ends of the supporting cable), signal collector and computer. It is required to monitor each monitored quantity in real time or quasi-real time, monitor the cable force of each supporting cable, and monitor the horizontal distance between the two supporting ends of each supporting cable. The software should have the following functions: the software part should be able to complete the process set in the first part of the present invention, that is, complete the monitoring, recording, control, storage, calculation, notification, and alarm that are required in the present invention and can be realized by computers. and other functions.

The inventive method specifically comprises:

a. Assuming that there are N cables in total, first determine the numbering rules of the cables, and number all the cables in the cable structure according to this rule, which will be used to generate vectors and matrices in subsequent steps;

b. Determine the specified measured points of the spatial coordinates to be monitored, and number all specified points; determine the spatial coordinate components to be monitored of each measurement point, and number all measured spatial coordinate components; the above-mentioned numbers are in the subsequent steps will be used to generate vectors and matrices; "all the monitored spatial coordinate data of the structure" is composed of all the above-mentioned measured spatial coordinate components; for convenience, in the present invention, the "monitored spatial coordinate data of the structure" is called is the "monitored quantity"; the number of measuring points shall not be less than the number of cables; the sum of the number of all measured spatial coordinate components shall not be less than the number of cables;

c. Establishing an initial virtual damage vector d _o using data that can express the health status of the cable, such as non-destructive testing data of the cable. If there is no non-destructive testing data of the cable and other data that can express the health status of the cable, the value of each element of the vector d ¹ _o is 0.

d. While establishing the initial virtual damage vector d _o , directly measure and calculate the initial values of all the monitored quantities of the cable structure to form the initial value vector C _o of the monitored quantities;

e. While establishing the initial virtual damage vector d _o and the initial value vector C _o of the monitored quantity, directly measure and calculate the initial cable force of all supporting cables to form the initial cable force vector F _o ; at the same time, according to the structural design data, The initial free lengths of all supporting cables are obtained from the as-built data to form the initial free length vector l _o ; at the same time, the initial geometric data of the cable structure are obtained according to the structural design data, as-built data or actual measurement; at the same time, all the The elastic modulus, density, and initial cross-sectional area of the cable;

f. Establish the initial mechanical calculation benchmark model A _o of the cable structure, establish the initial cable structure support coordinate vector U _o , and establish the current mechanical calculation benchmark model A ^t _o of the cable structure; according to the actual measurement data of the cable structure when the cable structure is completed, The measured data includes cable structure shape data, cable force data, tie rod tension data, cable structure support coordinate data, cable structure modal data, elastic modulus, density, and initial cross-sectional area of all cables.

Damage detection data and other data that can express the health status of the cable, according to the design drawing and as-built drawing, use the mechanical method to establish the initial mechanical calculation benchmark model A _o of the cable structure; if there is no actual measurement data of the cable structure when it is completed, then Before the health monitoring system is established, the cable structure is actually measured, and the measured data of the cable structure is also obtained. According to this data and the design drawing and as-built drawing of the cable structure, the initial mechanical calculation benchmark model A _o of the cable structure is also established by the mechanical method; No matter what method is used to obtain A _o , the cable structure calculation data based on A _o must be very close to the measured data, and the difference between them should not be greater than 5%; the cable structure support coordinate data corresponding to A _o constitutes the initial cable structure support coordinate vector U _o ; A _o and U _o are invariable; for the _convenience of description, it is named "the current mechanical calculation benchmark model ^{A t} _o of the cable structure". , A ^t _o is equal to A _o ; also for the convenience of description, it is named "cable structure measured support coordinate vector U ^t ". During the service process of the structure, the current data of the cable structure The data consists of "current cable structure measured support coordinate vector U ^t ", the elements of vector U ^t and the elements of the same position as vector U _o represent the coordinates of the same support in the same direction; for the convenience of description, the last update A ^t _o The current data of the cable structure support coordinates at the time is recorded as the current cable structure support coordinate vector U ^t _o ; at the beginning, A ^t _o is equal to A _o , and U ^t _o is equal to U _o ; the health status of the cable corresponding to A _o is determined by d _o describe;

g. When the health monitoring system starts to work, let A ^t _o be equal to A _o ; during the service process of the structure, the current data of the cable structure support coordinates are continuously measured, and all the current data of the cable structure support coordinates form the current measured support coordinate vector of the cable structure U ^t , according to the measured support coordinate vector U ^t of the current cable structure, update the current mechanical calculation benchmark model A ^t _o of the cable structure and the current cable structure support coordinate vector U ^t _o when necessary;

h. Carry out several mechanical calculations on the basis of the current mechanical calculation benchmark model A ^t _o of the cable structure, and obtain the numerical change matrix ΔC of the monitored quantity of the virtual unit damage of the cable structure and the nominal virtual unit damage vector D _u through calculation;

i. The current cable force of all the supporting cables of the cable structure is obtained through actual measurement to form the current cable force vector F; at the same time, the current measured values of all specified monitored quantities of the cable structure are obtained through actual measurement to form the "current value vector C of the monitored quantity" . The spatial coordinates of the two supporting end points of all supporting cables are obtained through actual measurement and calculation, and the difference in the horizontal component of the spatial coordinates of the two supporting end points is the horizontal distance between the two supporting end points. When numbering the elements of all vectors that appear in this step and before this step, the same numbering rule should be used, so as to ensure that the elements with the same number in each vector that appears in this step and before and after this step represent the same monitored quantity , corresponding to the relevant information defined by the vector to which the element belongs;

j. Define the current nominal virtual damage vector d _c and the current actual virtual damage vector d to be obtained. The number of elements of the damage vector d _o , d _c and d is equal to the number of cables, and there is a one-to-one correspondence between the elements of the damage vector and the cables, and the value of the elements of the damage vector represents the virtual damage degree or health status of the corresponding cable;

k. According to the existence of "the current numerical vector C of the monitored quantity" and "the initial numerical vector C _o of the monitored quantity", "the numerical change matrix of the virtual unit damage monitored quantity ΔC" and "the current nominal virtual damage vector d _c " The approximate linear relationship can be expressed as Equation 1. In Equation 1, other quantities except d _c are known, and the current nominal virtual damage vector d _c can be calculated by solving Equation 1;

C＝C _o +ΔC·d _c Formula 1

1. Using the relationship between the element d _j of the current actual virtual damage vector d expressed in formula 2, the element d _oj of the initial virtual damage vector d _o , and the element d _cj of the current nominal virtual damage vector d _c , the current actual virtual damage is calculated All elements of vector d.

d _j ＝1-(1-d _oj )(1-d _cj ) Formula 2

In Formula 2, j=1, 2, 3, ..., N.

Since the element value of the current actual virtual damage vector d represents the current actual virtual damage degree of the corresponding cable, that is, the actual degree of relaxation or the actual damage degree, the supporting cable corresponding to the element whose value is not 0 in the current actual virtual damage vector d is problematic Supporting cable, the problematic supporting cable may be a slack cable or a damaged cable, and its value reflects the degree of slack or damage;

m. Identify damaged cables from the problematic support cables identified in step 1, leaving slack cables remaining.

n. Use the current actual virtual damage vector d obtained in the first step to obtain the current actual virtual damage degree of the slack cable, use the current cable force vector F obtained in the i step, and use the two values of all supporting cables obtained in the i step The spatial coordinates of the support end points, using the initial free length vector l _o obtained in step e, using the elastic modulus, density, and initial cross-sectional area data of all cables obtained in step e, by combining the slack cables with the damaged The cable is mechanically equivalent to calculate the relaxation degree equivalent to the current actual virtual damage degree of the slack cable. The equivalent mechanical conditions are: the initial free length, geometric The characteristic parameters, density and mechanical characteristic parameters of the material are the same; 2. After relaxation or damage, the cable force and the total length after deformation of the two equivalent relaxed cables and damaged cables are the same. When the above two equivalent conditions are satisfied, the mechanical functions of such two supporting cables in the structure are exactly the same, that is, if the damaged cable is replaced by an equivalent slack cable, the cable structure will not change, and vice versa. Of course. According to the aforementioned mechanical equivalent conditions, the degree of relaxation of those cables judged to be slack is obtained. The degree of relaxation is the change in the free length of the supporting cables, that is, the length adjustment of the supporting cables whose force needs to be adjusted is determined. This enables slack detection and damage detection of the support cables. The cable force required for calculation is given by the corresponding element of the current cable force vector F.

In step g, according to the measured support coordinate vector U ^t of the current cable structure, the specific method for updating the current mechanical calculation benchmark model A ^t _{o of} the cable structure and the current cable structure support coordinate vector U ^t _o when necessary is as follows:

g1. After obtaining the measured support coordinate vector U ^t of the current cable structure, compare U ^t with U ^t _o , if U ^t is equal to U ^t _o , there is no need to update A ^t _o ;

g2. After obtaining the measured support coordinate vector U ^t of the current cable structure, compare U ^t with U ^t _o , if U ^t is not equal to U ^t _o , then A ^t _o needs to be updated. The update method is: first calculate U ^t The difference between U ^t and U _o , the difference between U t and U _o is the current support displacement of the current cable structure support relative to the cable structure support when A _o is established, and the current support displacement vector V is used to represent the support displacement. There is a one-to-one correspondence between the elements in the seat displacement vector V and the support displacement components. The value of an element in the current support displacement vector V corresponds to the displacement of a specified support in a specified direction, where the support displacement is in the gravity The component of the direction is the settlement of the support; the method to update A ^t _o is: apply the current support displacement constraint to the cable structure support in A _o , and the value of the current support displacement constraint is taken from the current support displacement vector V Corresponding to the value of the element, after applying the current support displacement constraint to the cable structure support in A _o , the final result is the updated current mechanical calculation benchmark model A ^t _o , while updating A ^t _o , the values of all elements of U ^t _o Also replace all element values of U ^t , that is, U ^t _o is updated, so that U ^t _o corresponding to A ^t _o is obtained correctly.

In step h, several mechanical calculations are performed on the basis of the current mechanical calculation benchmark model A ^t _o of the cable structure, and the numerical change matrix ΔC of the monitored quantity of the virtual unit damage of the cable structure and the specific value of the nominal virtual unit damage vector D _u are obtained through calculation. The method is:

h1. When the health monitoring system starts to work for the first time, directly follow the methods listed in step h2 to step h4 to obtain the cable structure virtual unit damage monitored variable matrix ΔC and the nominal virtual unit damage vector D _u ; later, if in step g A ^t _o has been updated, directly follow the methods listed in step h2 to step h4 to obtain the cable structure virtual unit damage monitored variable matrix ΔC and the nominal virtual unit damage vector D _u , if A ^t _o is not updated in step g , then go directly to step i here for follow-up work;

h2. Carry out several mechanical calculations on the basis of the current mechanical calculation benchmark model A ^t _o of the cable structure. The number of calculations is numerically equal to the number of all cables. If there are N cables, there will be N calculations. Each calculation assumes that there are only A cable adds virtual unit damage on the basis of the original virtual damage, the cable with virtual unit damage in each calculation is different from the cable with virtual unit damage in other calculations, and each time it is assumed that the cable with virtual unit damage The virtual unit damage value can be different from the virtual unit damage value of other cables. Use the “nominal virtual unit damage vector D _u ” to record the assumed unit damage of all cables, and obtain the current values of all monitored quantities for each calculation. The current values of all the monitored quantities form a "calculated current value vector of the monitored quantities". When it is assumed that the jth cable has unit damage, C _tj can be used to represent the corresponding "current calculated value vector C _tj of the monitored quantity". When numbering the elements of each vector in this step, the same numbering rule should be used with other vectors in the present invention, so that any element in each vector in this step can be guaranteed to express information about the same monitored quantity or the same object;

h3. Subtract the "initial numerical vector C _o of the monitored quantity" from the "currently calculated numerical vector C _tj of the monitored quantity" obtained by each calculation to obtain a vector, and then divide each element of the vector by this time After the virtual unit damage value assumed in the calculation, a "value change vector of the monitored quantity" is obtained; if there are N cables, there are N "value change vectors of the monitored quantity";

h4. A "virtual unit damage monitored quantity numerical change matrix ΔC" with N columns is sequentially composed of these N "monitored quantity numerical change vectors"; each column of the "virtual unit damage monitored quantity numerical change matrix ΔC" corresponds to Based on a "value change vector of the monitored quantity"; the numbering rules of the columns of the "virtual unit damage monitored quantity change matrix" are the same as the element numbering rules of the current nominal virtual damage vector _dc and the current actual virtual damage vector d.

Beneficial effects: the system and method disclosed in the present invention can monitor and evaluate the health state of the cable system (including all location of slack and damaged cords, and their degree of slack or damage). The systems and methods disclosed in the present invention are very beneficial for efficient health monitoring of cable systems.

Detailed ways

For the health monitoring of the cable system of the cable structure when there is support settlement, the invention discloses a system and method capable of reasonably and effectively monitoring the health status of each cable of the cable system of the cable structure. The following descriptions of embodiments of the invention are merely exemplary in nature, and are in no way intended to limit the application or uses of the invention.

In the event of settlement of a cable structure support, the present invention employs an algorithm for monitoring the health of the cable system in the cable structure (including cable slack and damage). During specific implementation, the following steps are one of various steps that may be taken.

Step 1: Determine the type, location and quantity of the quantity to be monitored, and number them. The specific process is:

First determine the numbering rule of the cable, and number all the cables according to this rule. This number will be used in subsequent steps to generate vectors and matrices.

Assuming that there are N cables, first determine the numbering rules of the cables, and number all the cables in the cable structure according to this rule, and the numbers will be used to generate vectors and matrices in subsequent steps.

Determine the specified measured points (i.e. all designated points representing structural space coordinates, K designated points are provided), number all designated points; determine the measured space coordinate component of each measured point (set each measured point There are L measured spatial coordinate components), numbering all specified measured spatial coordinate components. The above numbers will also be used to generate vectors and matrices in subsequent steps. "All the monitored spatial coordinate data of the structure" is described by the L spatial coordinate components of the K specified points on the structure determined above and passing through each specified point. The change of the structural space coordinates is all specified points, all specified Changes in the spatial coordinate components of . Each time there are M (M=K×L) measured or calculated values of spatial coordinate components to represent the spatial coordinate information of the structure. K and M shall not be less than the number N of supporting cables. For convenience, the "monitored spatial coordinate data of the structure" is referred to as "monitored quantity" in the present invention.

The second step: use the non-destructive testing data of the cable and other data that can express the health status of the cable to establish an initial virtual damage vector d _o . If there is no non-destructive testing data of the cable and other data that can express the healthy state of the cable, or when the initial state of the structure can be considered as a state of no damage and no relaxation, the value of each element of the vector d _o is 0.

Step 3: While establishing the initial virtual damage vector d _o , directly measure and calculate the initial values of all the monitored quantities of the cable structure to form the "initial value vector C _o of the monitored quantities"; at the same time, directly measure and calculate the cable structure The initial cable forces of all supporting cables of the structure form the "initial cable force vector F _o "; at the same time, the initial free lengths of all cables are obtained according to the structural design data and completion data, and form the "supporting cable initial free length vector l _o "; at the same time , the elastic modulus, density, and initial cross-sectional area of all cables are obtained from actual measurements or based on structural design and completion data.

Step 4: While establishing the initial virtual damage vector d ¹ _o , mature measurement methods can be used for cable force measurement, strain measurement, angle measurement and space coordinate measurement. The initial geometric shape data of the cable structure (for cable-stayed bridges, its initial bridge type data) can be obtained by direct measurement or calculated after measurement. The initial geometric shape data of the cable structure can be the spatial coordinate data of the end points of all cables plus a series of structural The spatial coordinate data of points is used to determine the geometric characteristics of the cable structure according to these coordinate data. For cable-stayed bridges, the initial geometric shape data can be the spatial coordinate data of all cable end points plus the spatial coordinate data of several points on both ends of the bridge, which is the so-called bridge type data.

Establish the initial mechanical calculation benchmark model A _o of the cable structure, establish the initial cable structure support coordinate vector U _o , and establish the current mechanical calculation benchmark model A ^t _o of the cable structure; The data includes cable structure shape data, cable force data, pull rod tension data, cable structure support coordinate data, cable structure modal data, measured data such as elastic modulus, density, and initial cross-sectional area of all cables, and nondestructive testing data of cables. and other data that can express the health state of the cable, according to the design drawing and the as-built drawing, use the mechanical method to establish the initial mechanical calculation benchmark model A _o of the cable structure; The actual measurement of the cable structure is carried out before the monitoring system, and the actual measurement data of the cable structure are also obtained. According to this data and the design drawing and as-built drawing of the cable structure, the initial mechanical calculation benchmark model A _o of the cable structure is also established by using the mechanical method; no matter what The cable structure calculation data based on A _o must be very close to the measured data, and the difference between them should not _{be greater than 5%; the cable structure support coordinate data corresponding to A o constitutes} the initial cable structure support coordinate vector U _o ; A _o and U _o ^are constant; for the convenience of description, it is named "the current mechanical calculation benchmark model A ^t _o of the cable structure". During the service process of the structure, A ^t _o will be updated continuously as needed. _o is equal to A _o ; also for the convenience of description, it is named "the measured support coordinate vector U ^t of the cable structure". The measured support coordinate vector U ^t of the current cable structure, the elements of the vector U ^t and the elements of the same position as the vector U _o represent the coordinates of the same support in the same direction; for the convenience of description, the last update of A ^to _o The current data of structural support coordinates is recorded as the current cable structural support coordinate vector U ^t _o ; at the beginning, A ^t _o is equal to A _o , and U ^t _o is equal to U _o ; the health state of the cable corresponding to A _o is described by d _o ;

Step 5: Install the hardware part of the cable structure health monitoring system. The hardware part includes at least: the monitored quantity monitoring system (for example, including space coordinate measurement system, signal conditioner, etc.), cable structure support coordinate monitoring system (for example, measuring with total station), cable force monitoring system (for example, including acceleration sensor , signal conditioner, etc.), the horizontal distance monitoring system of the two supporting ends of each supporting cable (such as measuring with a total station), signal (data) collector, computer and communication alarm equipment. Each monitored quantity, the cable force of each supporting cable and the horizontal distance between the two supporting ends of each supporting cable must be monitored by the monitoring system, and the monitoring system will transmit the monitored signal to the signal (data) collector; the signal It is transmitted to the computer through the signal collector; the computer is responsible for running the health monitoring software of the cable system of the cable structure, including recording the signal transmitted by the signal collector; , the owner and (or) designated personnel to call the police.

Step 6: Compile and install the software of the cable system health monitoring system running the cable structure on the monitoring computer. This software will complete the monitoring, recording, control, storage, calculation, notification, alarm and other functions required by the task of the present invention "the method for identifying slack support cables based on spatial coordinate monitoring when the bearing is settling" (i.e. this specific implementation method All the work that can be done by computer), and the health monitoring system can be generated periodically or by personnel to generate reports on the health of the cable system, and it can also automatically notify or prompt the monitoring personnel to notify according to the set conditions (such as damage reaching a certain value). Dedicated technicians perform the necessary calculations.

Step 7: When the health monitoring system starts to work, let A ^t _o be equal to A _o ; during the service process of the structure, the current data of the cable structure support coordinates are obtained by continuous actual measurement (such as measurement with a total station), and all the cable structure support coordinates The current data constitute the current cable structure measured support coordinate vector U ^t , according to the current cable structure measured support coordinate vector U ^t , update the current mechanical calculation benchmark model A ^t _{o of} the cable structure and the current cable structure support coordinate vector U ^t when necessary _o . The specific method is: after obtaining the actual measurement support coordinate vector U ^t of the current cable structure, compare U ^t with u ^t _o , if U ^t is equal to U ^t _o , there is no need to update A ^t _o ; After the support coordinate vector U ^t , compare U ^t and U ^t _o , if U ^t is not equal to U ^t _o , then A ^t _o needs to be updated. The method to update A ^t _o is: first calculate the difference between U ^t and U _o , the difference between U ^t and U _o is the current support displacement of the current cable structure support with respect to the cable structure support when A _o is established, and use the current The support displacement vector V represents the support displacement. There is a one-to-one correspondence between the elements in the current support displacement vector V and the support displacement components. The value of an element in the current support displacement vector V corresponds to the value of a specified support. A displacement in a specified direction, where the component of the support displacement in the direction of gravity is the settlement of the support; the method to update A ^t _o is: apply the current support displacement constraint to the cable structure support in A _o , and the current support displacement constraint The value of is taken from the value of the corresponding element in the current support displacement vector V. After applying the current support displacement constraint to the cable structure support in A _o , the final result is the updated current mechanical calculation benchmark model A ^t _o . At the same time as A ^t _o , all element values of U ^t _o are also replaced by all element values of U ^t , that is, U ^t _o is updated, so that U ^t _o corresponding to A ^t _o is obtained correctly.

Step 8: Carry out several mechanical calculations on the basis of the current mechanical calculation benchmark model A ^t _o of the cable structure, and obtain the numerical change matrix ΔC of the monitored quantity of the virtual unit damage of the cable structure and the nominal virtual unit damage vector D _u through calculation. The specific method is as follows:

a. When the health monitoring system starts working for the first time, directly follow the methods listed in step b to step d to obtain the cable structure virtual unit damage monitored variable matrix ΔC and the nominal virtual unit damage vector D _u ; later, if in the seventh step A ^t _o is updated, and the cable structure virtual unit damage monitored variable matrix ΔC and nominal virtual unit damage vector D _u are obtained directly according to the methods listed in step b to step d. If A ^t _o is not updated in the seventh step To update, go directly to the ninth step here for follow-up work;

b. Carry out several mechanical calculations on the basis of the current mechanical calculation benchmark model A ^to _o of the cable structure. The number of calculations is numerically equal to the number of all cables. There are N calculations with N cables. Each calculation assumes that there are only A cable adds virtual unit damage on the basis of the original virtual damage, the cable with virtual unit damage in each calculation is different from the cable with virtual unit damage in other calculations, and each time it is assumed that the cable with virtual unit damage The virtual unit damage value can be different from the virtual unit damage value of other cables. Use the “nominal virtual unit damage vector D _u ” to record the assumed unit damage of all cables, and obtain the current values of all monitored quantities for each calculation. The current values of all the monitored quantities form a "calculated current value vector of the monitored quantities". When it is assumed that the jth cable has unit damage, C _tj can be used to represent the corresponding "current calculated value vector C _tj of the monitored quantity". When numbering the elements of each vector in this step, the same numbering rule should be used with other vectors in the present invention, so that any element in each vector in this step can be guaranteed to express information about the same monitored quantity or the same object;

c. Subtract the "initial numerical vector C _o of the monitored quantity" from the "currently calculated numerical vector C _tj of the monitored quantity" obtained by each calculation to obtain a vector, and then divide each element of the vector by this time After the virtual unit damage value assumed in the calculation, a "value change vector of the monitored quantity" is obtained; if there are N cables, there are N "value change vectors of the monitored quantity";

d. A "virtual unit damage monitored quantity numerical change matrix ΔC" with N columns is formed in turn by these N "monitored quantity numerical change vectors"; each column of the "virtual unit damage monitored quantity numerical change matrix ΔC" corresponds to Based on a "value change vector of the monitored quantity"; the numbering rules of the columns of the "virtual unit damage monitored quantity change matrix" are the same as the element numbering rules of the current nominal virtual damage vector _dc and the current actual virtual damage vector d.

When numbering the elements of each vector in this step and thereafter, the same numbering rule should be used with other vectors in the present invention, so that it can be guaranteed that any element in each vector in this step has the same numbering as in other vectors. Elements express the related information of the same monitored quantity or the same object.

Step 9: Establish linear relationship error vector e and vector g. Using the previous data ("the initial value vector C _o of the monitored quantity", "the numerical change matrix of the virtual unit damage monitored quantity ΔC"), while performing each calculation in the eighth step, that is, in each calculation, it is assumed that the index There is only one cable in the system. While adding virtual unit damage on the basis of the original virtual damage, each calculation forms a "virtual damage vector d _t ". The number of elements in the virtual damage vector d _t is equal to the number of cables. The virtual damage Among all the elements of the vector d _t, the value of only one element is assumed to be the virtual unit damage value of the cable that increases the virtual unit damage in each calculation, the value of the other elements of d _t is 0, and the number of the element that is not 0 is the same as the assumption The corresponding relationship of the cable that increases the damage of the virtual unit is the same as that of the elements of the same number in other vectors and the corresponding relationship of the cable; put C _tj , C _o , ΔC, d _t into formula (13) (note that In formula (13), C is brought in by C _tj , d _c is brought in by d _t ), and a linear relationship error vector e is obtained, and a linear relationship error vector e is obtained for each calculation; there are N times of calculations if there are N cables, There are N linear relationship error vectors e, and these N linear relationship error vectors e are added to obtain a vector, and the new vector obtained after dividing each element of this vector by N is the final linear relationship error vector e. The vector g is equal to the final error vector e. Save the vector g on the computer hard disk running the health monitoring system software for use by the health monitoring system software.

"Initial cable force vector F _o ", "initial value vector C _o of the monitored quantity", "nominal virtual unit damage vector D _u ", "initial free length vector l _o ", "virtual unit damage value change of the monitored quantity The matrix ΔC" and parameters such as elastic modulus, initial cross-sectional area, and weight per unit length of all cables are stored in the form of data files on the hard disk of the computer running the health monitoring system software.

Step 10: Obtain the current cable force of all the supporting cables of the cable structure through actual measurement to form the current cable force vector F; at the same time, obtain the current measured values of all specified monitored quantities of the cable structure through actual measurement to form the "current value vector of the monitored quantity C". The spatial coordinates of the two supporting end points of all supporting cables are obtained through actual measurement and calculation, and the difference in the horizontal component of the spatial coordinates of the two supporting end points is the horizontal distance between the two supporting end points.

Step 11: According to "current (calculated or measured) numerical vector C of the monitored quantity" and "initial numerical vector C _o of the monitored quantity", "virtual unit damage monitored quantity numerical change matrix ΔC" and "current nominal There is an approximate linear relationship between the virtual damage vector d _c ” (see formula (9)), and the non-inferior solution of the current nominal virtual damage vector d _c of the cable system is calculated according to the multi-objective optimization algorithm.

There are many kinds of multi-objective optimization algorithms that can be used, such as: multi-objective optimization based on genetic algorithm, multi-objective optimization based on artificial neural network, multi-objective optimization algorithm based on particle swarm, multi-objective optimization based on ant colony algorithm, constraint method (Constran Method), Weighted Sum Method, Goal Attanment Method, etc. Since various multi-objective optimization algorithms are conventional algorithms, they can be easily implemented. This implementation step only uses the objective programming method as an example to give the process of solving the current nominal virtual damage vector _dc . The specific implementation process of other algorithms can be based on their specific The requirements of the algorithm are implemented in a similar fashion.

According to the goal programming method, formula (9) can be transformed into the multi-objective optimization problem shown in formula (29) and formula (30). In formula (29), γ is a real number, R is a real number field, and the space region Ω limits the vector The value range of each element of d _c (this embodiment requires that each element of vector d _c is not less than 0 and not greater than 1). Equation (29) means to find a real number γ with the smallest absolute value, so that Equation (30) is satisfied. G(d _c ) in formula (30) is defined by formula (31), and the product of weighted vector W and γ in formula (30) represents the allowable deviation between G(d _c ) and vector g in formula (30), g Refer to formula (15) for the definition of , and its value will be calculated in the eighth step. The vector W may be the same as the vector g during actual calculation. The specific programming implementation of the goal programming method already has a general program that can be directly adopted. According to the goal programming method, the current nominal damage vector d _c can be obtained.

minimize ¶

(29)

γ ∈ R, d _c ∈ Ω

G(d _c )-Wγ≤g (30)

G(d _c )=abs(ΔC·d _c -C+C _o ) (31)

After obtaining the current nominal virtual damage vector _dc , each element of the current actual virtual damage vector d can be obtained according to formula (17). A solution to determine the location of the problematic cable (ie, the virtually damaged cable, which may be damaged or slack) and the extent of its virtual damage. If the value of an element of the solved current actual virtual damage vector d is 0, it means that the cable corresponding to this element is intact without damage or slack; if its value is 100%, it means that the cable corresponding to this element is intact; The cable has completely lost its bearing capacity; if its value is between 0 and 100%, it means that the cable has lost a corresponding proportion of its bearing capacity.

Step 12: Since the element value of the current actual virtual damage vector d represents the virtual damage degree of the corresponding cable, it is possible to determine which cables may be damaged or loose and their possible damage degree or relaxation according to the current actual virtual damage vector However, whether these cables have been damaged or loosened needs to be identified. There are various identification methods, such as visual identification of the support cable by removing the protective layer of the support cable, or visual identification with the help of optical imaging equipment, or identification of whether the support cable is damaged by non-destructive testing methods, ultrasonic Flaw detection is a non-destructive testing method widely used at present. After the identification, those support cables with no damage found and virtual damage degree not equal to 0 are the cables with slack, that is, the cables whose force needs to be adjusted. According to formula (24) or formula (25), the degree of relaxation of these cables can be obtained ( That is, the cable length adjustment). In this way, the health monitoring of the cable system including the damage identification and the slack identification of the cable structure is realized.

Claims (1)

1. A method for identifying loose support cables based on spatial coordinate monitoring when bearing settlement is arranged, is characterized in that said method comprises: a. Assuming that there are N cables in total, first determine the numbering rules of the cables, and number all the cables in the cable structure according to this rule, which will be used to generate vectors and matrices in subsequent steps; b. Determine the measured points of the specified spatial coordinates to be monitored, and number all specified points; determine the spatial coordinate components to be monitored of each measurement point, and number all measured spatial coordinate components; The spatial coordinate data of the structure” is composed of all the above-mentioned measured spatial coordinate components; for convenience, the “monitored spatial coordinate data of the structure” is called the “monitored quantity”; the number of measuring points shall not be less than the number of cables; all the measured The sum of the number of coordinate components in the measurement space shall not be less than the number of cables; c. Use non-destructive testing data that can express the health state of the cable to establish the initial virtual damage vector d _o ; if there is no non-destructive testing data of the cable and other data that can express the healthy state of the cable, the value of each element of the vector d _o is 0; d. While establishing the initial virtual damage vector d _o , directly measure and calculate the initial values of all the monitored quantities of the cable structure to form the initial value vector C _o of the monitored quantities; e. While establishing the initial virtual damage vector d _o and the initial value vector C _o of the monitored quantity, directly measure and calculate the initial cable force of all supporting cables to form the initial cable force vector F _o ; at the same time, according to the structural design data, The initial free lengths of all supporting cables are obtained from the as-built data to form the initial free length vector l _o ; at the same time, the initial geometric data of the cable structure are obtained according to the structural design data, as-built data or actual measurement; at the same time, all the The elastic modulus, density, and initial cross-sectional area of the cable; f. Establish the initial mechanical calculation benchmark model A _o of the cable structure, establish the initial cable structure support coordinate vector U _o , and establish the current mechanical calculation benchmark model A ^t _o of the cable structure; according to the actual measurement data of the cable structure when the cable structure is completed, The measured data includes cable structure shape data, cable force data, tie rod tension data, cable structure support coordinate data, cable structure modal data, elastic modulus, density, initial cross-sectional area of all cables, and the ability to express the health of the cable Based on the design drawing and as-built drawing, use the mechanical method to establish the initial mechanical calculation benchmark model A _o of the cable structure; The cable structure is actually measured, and the measured data of the cable structure is also obtained. According to this data and the design drawing and as-built drawing of the cable structure, the initial mechanical calculation benchmark model A _o of the cable structure is also established by using mechanical methods; no matter what method is used to obtain A _o , the cable structure calculation data based on A _o must be very close to its measured data, and the difference between them should not be greater than 5%; the cable structure support coordinate data corresponding to A _o constitutes the initial cable structure support coordinate vector U _o ; A _o and U _o are invariant; for the convenience of description, it is named "the current mechanical calculation benchmark model A ^t _o of the cable structure". During the service process of the structure, A ^t _o will be updated continuously according to the needs. At the beginning, A ^t _o is equal to A _o ; Also for the convenience of description, it is named "the measured support coordinate vector U ^t of the current cable structure". During the service process of the structure, the current data of the cable structure support coordinates are continuously measured. The measured support coordinate vector U ^t ”, the elements of the vector U ^t _and the elements at the same position as the vector U _o represent the coordinates of the same support in ^the same direction; The current coordinate data is recorded as the current cable structure support coordinate vector U ^t _o ; at the beginning, A ^t _o is equal to A _o , and U ^t _o is equal to U _o ; the health state of the cable corresponding to A _o is described by d _o ; g. When the health monitoring system starts to work, let A ^t _o be equal to A _o ; during the service process of the structure, the current data of the cable structure support coordinates are continuously measured, and all the current data of the cable structure support coordinates form the current measured support coordinate vector of the cable structure U ^t , according to the measured support coordinate vector U ^t of the current cable structure, update the current mechanical calculation benchmark model A ^t _o of the cable structure and the current cable structure support coordinate vector U ^t _o according to steps g1 and g2; g1. After obtaining the measured support coordinate vector U ^t of the current cable structure, compare U ^t with U ^t _o , if U ^t is equal to U ^t _o , there is no need to update A ^t _o ; g2. After obtaining the measured support coordinate vector U ^t of the current cable structure, compare U ^t with U ^t _o , if U ^t is not equal to U ^t _o , then A ^t _o needs to be updated. The update method is: first calculate U ^t The difference between U ^t and U _o , the difference between U t and U _o is the current support displacement of the current cable structure support relative to the cable structure support when A _o is established, and the current support displacement vector V is used to represent the support displacement. There is a one-to-one correspondence between the elements in the seat displacement vector V and the support displacement components. The value of an element in the current support displacement vector V corresponds to the displacement of a specified support in a specified direction, where the support displacement is in the gravity The component of the direction is the settlement of the support; the method to update A ^t _o is: apply the current support displacement constraint to the cable structure support in A _o , and the value of the current support displacement constraint is taken from the current support displacement vector V Corresponding to the value of the element, after applying the current support displacement constraint to the cable structure support in A _o , the final result is the updated current mechanical calculation benchmark model A ^t _o , while updating A ^t _o , the values of all elements of U ^t _o Also replace all element values of U ^t , that is, U ^t _o is updated, so that U ^t _o correctly corresponding to A ^t _o is obtained; h. Carry out several mechanical calculations according to the steps h1, h2, h3, and h4 on the basis of the current mechanical calculation benchmark model A ^to of the cable structure, and obtain the numerical change _matrix ΔC and the nominal virtual unit of the virtual unit damage of the cable structure through calculation Damage vector D _u ; h1. When the health monitoring system starts working for the first time, directly follow the methods listed in step h2 to step h4 to obtain the numerical change matrix ΔC of the monitored quantity of the virtual unit damage of the cable structure and the nominal virtual unit damage vector D _u ; later, if in step g A ^t _o has been updated, and the numerical change matrix ΔC of the monitored quantity of the virtual unit damage of the cable structure and the nominal virtual unit damage vector D _u are obtained directly according to the methods listed in step h2 to step h4. If A ^t _o is not updated in step g To update, then go directly to step i here for follow-up work; h2. Carry out several mechanical calculations on the basis of the current mechanical calculation benchmark model A ^t _o of the cable structure. The number of calculations is numerically equal to the number of all cables. If there are N cables, there will be N calculations. Each calculation assumes that there are only A cable adds virtual unit damage on the basis of the original virtual damage, the cable with virtual unit damage in each calculation is different from the cable with virtual unit damage in other calculations, and each time it is assumed that the cable with virtual unit damage The virtual unit damage value can be different from the virtual unit damage value of other cables. Use the “nominal virtual unit damage vector D _u ” to record the assumed unit damage of all cables, and obtain the current values of all monitored quantities for each calculation. The current values of all the monitored quantities form a "currently calculated numerical vector of the monitored quantity"; when it is assumed that the jth root cable has unit damage, C _tj can be used to represent the corresponding "currently calculated numerical vector of the monitored quantity C _tj "; when numbering the elements of each vector in this step, the same numbering rule should be used with other vectors, so that it can ensure that any element in each vector in this step expresses Information about the same monitored quantity or the same object; h3. Subtract the "initial numerical vector C _o of the monitored quantity" from the "currently calculated numerical vector C _tj of the monitored quantity" obtained by each calculation to obtain a vector, and then divide each element of the vector by this time After the virtual unit damage value assumed in the calculation, a "value change vector of the monitored quantity" is obtained; if there are N cables, there are N "value change vectors of the monitored quantity"; h4. A "virtual unit damage monitored quantity numerical change matrix ΔC" with N columns is sequentially composed of these N "monitored quantity numerical change vectors"; each column of the "virtual unit damage monitored quantity numerical change matrix ΔC" corresponds to Based on a "value change vector of the monitored quantity"; the numbering rules of the columns of the "virtual unit damage monitored quantity change matrix" are the same as the element numbering rules of the current nominal virtual damage vector _dc and the current actual virtual damage vector d; i. The current cable force of all the supporting cables of the cable structure is obtained through actual measurement to form the current cable force vector F; at the same time, the current measured values of all specified monitored quantities of the cable structure are obtained through actual measurement to form the "current value vector C of the monitored quantity" ; The spatial coordinates of the two supporting end points of all supporting cables are obtained through actual measurement and calculation, and the difference in the horizontal component of the spatial coordinates of the two supporting end points is the horizontal distance between the two supporting end points. When numbering the elements of all vectors that appear in this step and before this step, the same numbering rule should be used, so as to ensure that the elements with the same number in each vector that appears in this step and before and after this step represent the same monitored quantity , corresponding to the relevant information defined by the vector to which the element belongs; j. Define the current nominal virtual damage vector d _c and the current actual virtual damage vector d to be sought; the number of elements of the damage vectors d _o , d _c and d is equal to the number of cables, and the elements of the damage vector and the cables are one-to-one Correspondence, the element value of the damage vector represents the virtual damage degree or health status of the corresponding cable; k. According to the existence of "the current numerical vector C of the monitored quantity" and "the initial numerical vector C _o of the monitored quantity", "the numerical change matrix of the virtual unit damage monitored quantity ΔC" and "the current nominal virtual damage vector d _c " The approximate linear relationship can be expressed as formula 1. In formula 1, other quantities except d _c are known, and the current nominal virtual damage vector d _c can be calculated by solving formula 1; C＝C _o +ΔC·d _c Formula 1 1. Using the relationship between the element d _j of the current actual virtual damage vector d expressed in formula 2, the element d _oj of the initial virtual damage vector d _o , and the element d _cj of the current nominal virtual damage vector d _c , the current actual virtual damage is calculated all elements of vector d; d _j ＝1-(1-d _oj )(1-d _cj ) Formula 2 In formula 2, j=1, 2, 3,..., N; Since the element value of the current actual virtual damage vector d represents the current actual virtual damage degree of the corresponding cable, that is, the actual degree of relaxation or the actual damage degree, the supporting cable corresponding to the element whose value is not 0 in the current actual virtual damage vector d is problematic Supporting cable, the supporting cable in question is a slack cable or a damaged cable, and its value reflects the degree of slack or damage; m. Identify damaged cables from the problematic support cables identified in step 1, leaving slack cables; n. Use the current actual virtual damage vector d obtained in the first step to obtain the current actual virtual damage degree of the slack cable, use the current cable force vector F obtained in the i step, and use the two values of all supporting cables obtained in the i step The spatial coordinates of the support end points, using the initial free length vector l _o obtained in step e, using the elastic modulus, density, and initial cross-sectional area data of all cables obtained in step e, by combining the slack cables with the damaged The cable is mechanically equivalent to calculate the relaxation degree equivalent to the current actual virtual damage degree of the slack cable. The equivalent mechanical conditions are: the initial free length, geometric The characteristic parameters, density and mechanical characteristic parameters of the material are the same; 2. After relaxation or damage, the cable force and the total length after deformation of the two equivalent slack cables and damaged cables are the same; when the above two equivalent conditions are satisfied, such two The mechanical functions of the supporting cables in the structure are exactly the same, that is, if the damaged cable is replaced by an equivalent slack cable, the cable structure will not change, and vice versa; It is judged as the slack degree of the slack cable, which is the change of the free length of the support cable, that is, the cable length adjustment of those support cables whose force needs to be adjusted is determined; in this way, the slack identification and damage identification of the support cable are realized. The cable force required for calculation is given by the corresponding element of the current cable force vector F.