CN111077021A - Loading device of double-bead cementing model under complex stress - Google Patents
Loading device of double-bead cementing model under complex stress Download PDFInfo
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- CN111077021A CN111077021A CN202010038216.2A CN202010038216A CN111077021A CN 111077021 A CN111077021 A CN 111077021A CN 202010038216 A CN202010038216 A CN 202010038216A CN 111077021 A CN111077021 A CN 111077021A
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- 239000011324 bead Substances 0.000 title claims abstract description 111
- 238000005096 rolling process Methods 0.000 claims abstract description 8
- 238000006073 displacement reaction Methods 0.000 claims description 69
- 238000005520 cutting process Methods 0.000 claims description 14
- 230000009977 dual effect Effects 0.000 claims description 2
- 238000012360 testing method Methods 0.000 description 45
- 238000005452 bending Methods 0.000 description 22
- 238000000034 method Methods 0.000 description 19
- 230000008569 process Effects 0.000 description 18
- 230000009471 action Effects 0.000 description 14
- 239000002245 particle Substances 0.000 description 12
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- 229920000647 polyepoxide Polymers 0.000 description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 9
- 230000006835 compression Effects 0.000 description 9
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- 238000010008 shearing Methods 0.000 description 8
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- 239000004576 sand Substances 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 4
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- 239000002689 soil Substances 0.000 description 4
- 238000012999 compression bending Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000010687 lubricating oil Substances 0.000 description 3
- 239000006004 Quartz sand Substances 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
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- 230000001276 controlling effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
- G01N3/06—Special adaptations of indicating or recording means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/20—Investigating strength properties of solid materials by application of mechanical stress by applying steady bending forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0019—Compressive
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0023—Bending
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0025—Shearing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0026—Combination of several types of applied forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
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Abstract
The invention discloses a loading device of a double-bead cementing model under complex stress, which comprises a bottom plate, a rolling shaft, a sample cushion block, a lower cushion block, an upper cushion block, a first sensor group, a second sensor group and a connecting piece. The rolling shaft is arranged on the bottom plate; the lower cushion block is arranged on the roller, and the end part of the lower cushion block is connected with the horizontal load counter-force end; the upper cushion block is arranged above the lower cushion block, and the end part of the upper cushion block is connected with the horizontal load output end; the sample cushion blocks are respectively arranged in the third groove and the fifth groove and are respectively fixedly connected with the lower cushion block and the upper cushion block; one end of the connecting piece is inserted into the fourth groove and is hinged with the upper cushion block, and the other end of the connecting piece is connected with the linear guide rail end; the double-bead cementing model is arranged between the upper cushion block and the lower cushion block and is respectively fixedly connected with the sample cushion blocks on the upper cushion block and the lower cushion block; the roller, the sample cushion block and the connecting piece are coaxially arranged. When the double-bead cementing model is used, the double-bead cementing model is required to be installed on double-shaft loading equipment, and mechanical properties of the double-bead cementing model in a complex stress state are tested by loading different vertical loads and horizontal loads.
Description
Technical Field
The invention relates to the technical field of geotechnical engineering experimental equipment, in particular to a loading device for a double-bead cementing model under complex stress.
Background
The natural cemented sand is widely applied to actual engineering as a typical structural soil body material. At present, most researches on the mechanical behavior of the cemented sand stay in a macroscopic level, the understanding on the interaction mechanism of internal particles is lacked, and the connection between the crushing behavior of the cemented sand and the macroscopic mechanical response under the particle scale is not clear. This essentially limits our overall understanding of structural soils such as cemented sand. Only by deeply mastering the evolution law and the damage mechanism of the internal structure of the cemented sand from macro to micro from phenomena to essence can the prevention and treatment measures for fundamentally dealing with the related disasters in the actual engineering be provided. Therefore, the research on the crushing mode and the micro damage mechanism of the cemented sand particles is developed, the real mechanical property of the micro cemented sand particles is mastered, and the method has important theoretical value and practical significance for further improving the multi-scale mechanical mechanism research of structural soil and geotechnical engineering construction.
An ideal double-particle contact cementing model is manufactured in Jiangming mirror, grandyungjust, Liliqing, test research of two cementing particle micromechanics models under complex stress, geotechnical engineering report 2011b,33(3), 354 and 360' Jiangming mirror and the like. In this model, the cemented grain is idealized as two identical round section aluminum bars with the contact locations integrally bonded by epoxy. They further developed loading devices for applying normal, tangential and moment forces to the contact pattern. The experimental results show that the failure mode of two cemented aluminum bars depends on the way in which they are cemented: for contact bonding, the force-displacement curve exhibits strain hardening in the normal compression test and elastic brittle plasticity in the shear test. Whereas for parallel bonds, the force-displacement curve shows a tendency to strain soften in compression and elastoplastic softening in shear. In the torsional test, they noted that the torque-rotation angle dependence exhibited elastoplastic softening, both for the contact bond and parallel bond models. The peak strength of the cemented metal bars in both shear and torsion tests was positively correlated to the applied normal force, a relationship more pronounced for the contact bond model.
In the literature, the aluminum bar in a contact model is improved into an aluminum hemisphere by a Jiangming mirror in Jiangming mirror, gold tree building, Liu Wei, Liujun and particle-to-particle cemented contact mechanical property three-dimensional test research, geotechnical mechanics 2015,36 (increase 1): 9-13'. The research makes breakthrough progress on quantitative description of interparticle cementation, but the metallic aluminum and the epoxy resin cannot accurately express the mechanical properties of the natural rock-soil material, and reliable related research on particle size is still limited due to the large size of a test model; and the influence of quantitative description parameters such as the sphericity, roundness, length-width ratio, surface roughness, irregularity and the like of morphological characteristics of the particles on the mechanical properties of the particles is ignored.
Accordingly, further improvements and improvements are needed in the art.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a loading device which can test a series of complex loads such as compression shear, compression bending and shear combination and the like of a double-bead cementing model prepared from cementing materials such as natural quartz sand, cement and the like.
The purpose of the invention is realized by the following technical scheme:
the utility model provides a loading device of two pearl cementation models under complicated stress, loading device installs on biax loading equipment, includes bottom plate, roller bearing, sample cushion, lower cushion, goes up the cushion, is used for measuring the first sensor group of the symmetry setting of vertical displacement, the second sensor group of the symmetry setting of measurement horizontal displacement and connecting piece.
Specifically, the bottom plate is horizontally placed on a horizontally movable base, and a first groove for mounting and positioning the roller is formed in the bottom plate. The rolling shaft is arranged on the bottom plate and is positioned in the first groove. The lower cushion block is arranged on the roller, a second groove matched with the roller in a positioning mode is formed in the bottom of the lower cushion block, a third groove used for installing the sample cushion block is formed in the top of the lower cushion block, and the end portion of the lower cushion block is connected with the horizontal load counter-force end. The upper cushion block is arranged above the lower cushion block, a fourth groove used for being connected with the connecting piece is formed in the top of the upper cushion block, a fifth groove used for installing the sample cushion block is formed in the bottom of the upper cushion block, and the end portion of the upper cushion block is connected with the horizontal load output end. And the sample cushion blocks are respectively arranged in the third groove and the fifth groove and are respectively fixedly connected with the lower cushion block and the upper cushion block. The first sensor group is arranged on the upper cushion block. One end of the connecting piece is inserted into the fourth groove and hinged with the upper cushion block, and the other end of the connecting piece is connected with the linear guide rail end. The double-bead cementing model is arranged between the upper cushion block and the lower cushion block and is respectively fixedly connected with the sample cushion blocks on the upper cushion block and the lower cushion block. The roller, the sample cushion block and the connecting piece are coaxially arranged.
Furthermore, in order to facilitate the installation of the first sensor set, the loading device of the invention further comprises a clamping plate for fixedly installing the first sensor set. The splint adopts L type structural design, is equipped with the mounting hole that is used for the first sensor group of chucking, the cutting seam and the fixed orifices of being convenient for installation on it. The mounting hole vertically penetrates through the clamping plate. The cutting seam extends from the edge of the splint to the mounting hole and penetrates the splint. The fixing hole is arranged on the side surface of the clamping plate, and the axis of the fixing hole is perpendicular to the cutting seam and penetrates through the cutting seam.
Furthermore, in order to accurately measure the horizontal displacement of the upper cushion block, the loading device further comprises a second sensor group for measuring the horizontal displacement of the upper cushion block. The second sensor group adopts two linear displacement sensors, is arranged on the upper cushion block and is fixedly connected with the upper cushion block.
As a preferable scheme of the invention, the upper part of the connecting piece is of a cylindrical structure and is connected with the linear guide rail end of the double-shaft loading device, and the lower part of the connecting piece is provided with a through hole which is hinged with the upper cushion block and is horizontally arranged.
As a preferred scheme of the invention, the upper cushion block and the lower cushion block are both designed by adopting an L-shaped structure, the vertical section of the upper cushion block is connected with the horizontal load output end, and the vertical section of the lower cushion block is connected with the horizontal load counter-force end.
As a preferable aspect of the present invention, the first displacement sensor group employs two linear displacement sensors.
As a preferable scheme of the present invention, the first groove and the second groove are designed to have a circular arc groove structure, and diameters of the first recess and the second recess are consistent with a diameter of the roller. And the third groove, the fourth groove and the fifth groove are all designed by adopting a cuboid groove structure.
The working process and principle of the invention are as follows:
the operation process of the compression-shear test is as follows:
1. and placing the prefabricated double-bead cemented model in the arc-shaped groove of the sample cushion block, adjusting the double-bead cemented model to be in a vertical state, and smearing a small amount of epoxy resin on the bottom of the double-bead cemented model to bond the bottom of the double-bead cemented model and the sample cushion block so as to keep the vertical state of the double-bead cemented model. After the epoxy resin is hardened, the sample cushion block containing the double-bead cementing model is placed in the rectangular groove of the L-shaped lower cushion block. Similarly, a small amount of epoxy resin is coated on the other sample cushion block arranged in the lower rectangular groove of the L-shaped upper cushion block and the top of the double-bead cementing model to bond the top of the double-bead cementing model with the sample cushion block, and then the upper and lower sample cushion blocks are fixed by screwing the bolt at the phi 2 threaded hole;
2. the loading device is installed on a double-shaft loading device, so that the intersection of the vertical part of the L-shaped upper cushion block and the central horizontal axis of the double-bead cementing model bears the horizontal load generated by the stepping motor, and two linear displacement sensors are symmetrically arranged on two sides of the intersection of the horizontal central axis of the double-bead cementing model and the vertical part of the upper cushion block and used for measuring the horizontal displacement of the L-shaped upper cushion block. Similarly, the intersection of the horizontal part of the L-shaped upper cushion block and the central vertical axis of the double-bead cemented model is subjected to vertical load generated by another stepping motor, two linear displacement sensors are symmetrically arranged on two sides of the intersection point of the vertical central axis of the double-bead cemented model and the horizontal part of the upper cushion block, and the two linear displacement sensors are fixed in the clamping plate and used for measuring the vertical displacement of the L-shaped upper cushion block. Coating lubricating oil on each contact point, and enabling each part to be in good contact;
3. during the test, a constant vertical load is firstly applied to enable the double-bead cementing model to be in a vertical state, and then a horizontal load is applied. And displacement control is used during horizontal loading, and the loading rate is set according to the requirements of the test. The double-bead cemented model is damaged under the combined action of horizontal load and vertical load, two horizontal displacement values are measured by the first sensor group, and the horizontal displacement value of the double-bead cemented model can be obtained by calculating the arithmetic mean value of the two horizontal displacement values.
The operation process of the bending test is as follows:
the test preparation stage is the same as the compression shear test operation processes 1 and 2;
the connecting piece can drive the whole horizontal migration of loading device along linear guide rail horizontal migration, and the vertical step motor position that provides vertical load remains unchanged to the effect position of vertical load is controlled. During a bending test, an eccentric distance exists between the vertical central axis of the double-bead cementing model and a vertical load, so that a bending moment is generated, and no horizontal load is applied in the test, namely no shearing force is generated. And finally, calculating the corner of the double-bead cementing model according to the ratio of the difference between two horizontal displacement values measured by the first sensor group to the distance between two linear displacement sensors in the first sensor group.
The bending and shearing combined test operation process comprises the following steps:
the test preparation stage is the same as the compression shear test operation processes 1 and 2;
the height of the loading device and the height of the counter force end lifting platform are adjusted to enable the whole loading device and the counter force end to move in the vertical direction, and the position of a horizontal stepping motor providing horizontal load is kept unchanged, so that the action position of the horizontal load is controlled. During the bending shear combined test, a vertical load acts on a vertical central axis of the double-bead cemented model, a distance exists between an acting point of a horizontal load output end and a horizontal central axis of the double-bead cemented model, a counter-force end acts on the horizontal central axis of the double-bead cemented model, a pair of horizontal forces with equal size and opposite directions are generated by the horizontal load output end and the counter-force end, and the horizontal forces are not on the same straight line to form a bending moment acting on the double-bead cemented model. And finally, calculating the horizontal displacement and the corner of the double-bead cementing model according to the measured horizontal displacement and vertical displacement of the L-shaped upper cushion block and the geometric relationship between the L-shaped upper cushion block and the double-bead cementing model.
Compared with the prior art, the invention also has the following advantages:
(1) the loading device of the double-bead cementing model under the complex stress can be used for carrying out a series of complex load tests combining compression shearing, compression bending and compression bending shearing on the double-bead cementing model prepared from cementing materials such as natural quartz sand, cement and the like, and can be used for reducing the destructive behavior and the mechanical property of the natural double-bead cementing model under the complex stress condition to the maximum extent.
(2) The loading device for the double-bead cementing model under the complex stress provided by the invention adopts the detachable sample cushion block, so that the double-bead cementing model can be conveniently placed and replaced and the sample cushion block can be conveniently cleaned, and the test efficiency is greatly improved.
(3) The loading device for the double-bead cementing model under the complex stress simplifies the installation process of the linear displacement sensor by utilizing the design of the reserved cutting seam in the clamping plate, can adjust the disassembly and the fixation by only controlling the tightness of the screw, not only prevents the damage of the linear displacement sensor caused by too tight hooping, but also avoids the experiment error caused by the shake of the linear displacement sensor during the experiment due to the incomplete fixation of the linear displacement sensor.
(4) One set of loading device can realize multiple loading paths simultaneously.
(5) The linear displacement sensors are symmetrically arranged, and the displacement and the rotation angle of the double-bead cementing model in the loading process can be measured simultaneously.
Drawings
FIG. 1 is a schematic structural diagram of a loading device for a two-bead bond model under complex stress according to the present invention.
Fig. 2 is a schematic structural view of a roller according to the present invention.
Fig. 3 is a schematic structural diagram of the base plate provided by the present invention.
Fig. 4 is a schematic structural diagram of a sample mat provided by the present invention.
Fig. 5 is a schematic structural diagram of the lower cushion block provided by the present invention.
Fig. 6 is a schematic structural diagram of an upper cushion block provided by the present invention.
Fig. 7 is a perspective view of an upper mat provided by the present invention.
Fig. 8 is a schematic structural view of the connector provided by the present invention.
Fig. 9 is a schematic structural view of the splint provided by the present invention.
FIG. 10 is a schematic view of the loading of the compression-shear test provided by the present invention
FIG. 11 is a front view of a loading apparatus for a two-bead bond model under complex stress as provided by the present invention.
FIG. 12 is a left side view of a loading apparatus for a two-bead bond model under complex stress as provided by the present invention.
FIG. 13 is a top view of a loading apparatus for a two-bead bond model under complex stress as provided by the present invention.
FIG. 14 is a perspective view of a loading apparatus for a two-bead bond model under complex stress as provided by the present invention.
The reference numerals in the above figures illustrate:
1-a rolling shaft, 2-a bottom plate, 21-an arc-shaped groove/a first groove, 3-a sample cushion block, 31-a circular groove, 4-an L-shaped lower cushion block/a lower cushion block, 41-an arc-shaped groove/a second groove, 42-a phi 2 threaded hole, 43-a rectangular groove/a third groove, 5-an L-shaped upper cushion block/an upper cushion block, 51-a vertical part, 52-a horizontal part, 521-a phi 2 threaded hole, 522-a phi 4 threaded hole, 523-an upper rectangular groove/a fourth groove, 524-a phi 4 threaded through hole, 525-a lower rectangular groove/a fifth groove, 6-a connecting piece, 61-a phi 4 threaded through hole, 7-a clamping plate, 71-a phi 3 threaded through hole, 72-a cutting seam, 73-a circular through hole/a mounting hole, 74-phi 4 threaded through holes, 8-double-bead cementing model, 9-linear guide rail, 10-base, 11-ball bearing, 12-lifting platform, 13-horizontal load and 14-vertical load.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention is further described below with reference to the accompanying drawings and examples.
Example 1:
as shown in fig. 1 to 14, the present embodiment discloses a loading device for a two-bead bond model under complex stress, which is installed on a dual-axis loading apparatus and mainly includes a bottom plate 2, a roller 1, a sample pad 3, a lower pad 4, an upper pad 5, a first sensor group and a second sensor group for measuring displacement, and a connecting member 6.
Specifically, the bottom plate 2 is horizontally placed on a horizontally movable base 10 of the double-shaft loading device, and a first groove 21 for installing and positioning the roller 1 is formed in the bottom plate. The roller 1 is arranged on the bottom plate 2 and is positioned in the first groove 21. The lower cushion block 4 is arranged on the roller 1, the bottom of the lower cushion block is provided with a second groove 41 which is matched with the roller 1 in a positioning way, the top of the lower cushion block is provided with a third groove 43 which is used for installing the sample cushion block 3, and the end part of the lower cushion block is connected with the horizontal load counter-force end. The upper cushion block 5 is arranged above the lower cushion block 4, the top of the upper cushion block is provided with a fourth groove 523 used for being connected with the connecting piece 6, the bottom of the upper cushion block is provided with a fifth groove 525 used for installing the sample cushion block 3, and the end part of the upper cushion block is connected with a horizontal load output end. The sample cushion block 3 is respectively arranged in the third groove 43 and the fifth groove 525 and is respectively fixedly connected with the lower cushion block 4 and the upper cushion block 5. The first sensor group is mounted on the upper cushion block 5. One end of the connecting piece 6 is inserted into the fourth groove 523 and hinged with the upper cushion block 5, and the other end is connected with the end of the linear guide rail 9. The double-bead cementing model 8 is arranged between the upper cushion block 5 and the lower cushion block 4 and is respectively fixedly connected with the sample cushion blocks 3 on the upper cushion block 4 and the lower cushion block 4. The roller 1, the sample cushion block 3 and the connecting piece 6 are coaxially arranged.
Further, in order to facilitate the installation of the first sensor set, the loading device of the present invention further includes a clamp plate 7 for fixedly installing the first sensor set. The clamping plate 7 is designed to be of an L-shaped structure, and is provided with a mounting hole 73 for clamping the first sensor group, a cutting seam 72 convenient to mount and a fixing hole. The mounting hole 73 vertically penetrates the chucking plate 7. The cutting slit 72 extends from the edge of the splint 7 to the mounting hole 73 and penetrates the splint 7. The fixing holes are provided on the side of the splint 7 with an axis perpendicular to and passing through the cutting slits 72.
Further, in order to accurately measure the horizontal displacement of the upper cushion block 5, the loading device of the invention further comprises a second sensor group for measuring the horizontal displacement of the upper cushion block 5. The second sensor group adopts two linear displacement sensors, is symmetrically arranged on the upper cushion block 5 and is fixedly connected with the upper cushion block 5.
As a preferable scheme of the invention, the upper part of the connecting piece 6 is of a cylindrical structure and is connected with the end of a linear guide rail 9 of the double-shaft loading device, and the lower part of the connecting piece is provided with a through hole which is hinged with the upper cushion block 5 and is horizontally arranged.
As a preferred scheme of the invention, the upper cushion block 5 and the lower cushion block 4 are both designed by adopting an L-shaped structure, the vertical section of the upper cushion block is connected with the horizontal load output end, and the vertical section of the lower cushion block is connected with the horizontal load counter-force end.
In a preferred embodiment of the present invention, the first sensor group employs two linear displacement sensors.
As a preferable scheme of the present invention, the first groove 21 and the second groove 41 are designed to have a circular arc groove structure, and the diameters of the first recess and the second recess are the same as the diameter of the roller 1. The third groove 43, the fourth groove 523 and the fifth groove 525 are all designed by a cuboid groove structure.
The working process and principle of the invention are as follows:
the operation process of the compression-shear test is as follows:
1. placing the prefabricated double-bead cemented model 8 in the arc-shaped groove of the sample cushion block 3, firstly adjusting the double-bead cemented model 8 to be in a vertical state, and smearing a small amount of epoxy resin on the bottom of the double-bead cemented model 8 to bond the bottom of the double-bead cemented model 8 with the sample cushion block 3 so as to keep the vertical state of the double-bead cemented model 8. After the epoxy resin is hardened, the sample cushion block 3 containing the double-bead cementing model 8 is placed in the rectangular groove of the L-shaped lower cushion block 4. Similarly, coating a small amount of epoxy resin on the other sample cushion block 3 arranged in the lower rectangular groove of the L-shaped upper cushion block 5 and the top of the double-bead cementing model 8 to bond the top of the double-bead cementing model 8 with the sample cushion block, and then screwing bolts at a phi 2 threaded hole and a phi 2 threaded hole to fix the upper and lower sample cushion blocks 3;
2. the loading device is installed on a double-shaft loading device, so that the intersection of the vertical part of the L-shaped upper cushion block 5 and the central horizontal axis of the double-bead cemented model 8 bears the horizontal load 13 generated by the stepping motor, and two linear displacement sensors are symmetrically arranged on two sides of the intersection of the horizontal central axis of the double-bead cemented model 8 and the vertical part 51 of the upper cushion block and used for measuring the horizontal displacement of the L-shaped upper cushion block 5. Similarly, the intersection of the horizontal part of the L-shaped upper cushion block 5 and the central vertical axis of the double-bead cemented model 8 is subjected to a vertical load 14 generated by another stepping motor, and two other linear displacement sensors are symmetrically arranged on two sides of the intersection of the vertical central axis of the double-bead cemented model and the horizontal part of the L-shaped upper cushion block 5, and the two linear displacement sensors are fixed in the clamping plate 7 and used for measuring the vertical displacement of the L-shaped upper cushion block 5. Coating lubricating oil on each contact point, and enabling each part to be in good contact;
3. for testing, a constant vertical load is applied to hold the two-bead bond model 8 in an upright position, followed by a horizontal load 13. And displacement control is used during horizontal loading, and the loading rate is set according to the requirements of the test. The double-bead cemented model 8 is damaged under the combined action of the horizontal load 13 and the vertical load 14, two horizontal displacement values are measured by the first sensor group, and the horizontal displacement value of the double-bead cemented model can be obtained by calculating the arithmetic mean value of the two horizontal displacement values.
The operation process of the bending test is as follows:
the test preparation stage is the same as the compression shear test operation processes 1 and 2;
the connecting piece 6 can move horizontally along the linear guide rail 9 to drive the whole loading device to move horizontally, and the position of a vertical stepping motor for providing vertical load is kept unchanged, so that the action position of the vertical load 14 is controlled. During a bending test, an eccentric distance exists between the vertical central axis of the double-bead cementing model 8 and the vertical load 14, so that a bending moment is generated, and no horizontal load 13 is applied in the test, namely no shearing force is generated. The double-bead cemented model 8 is damaged under the combined action of the vertical load 14 and the bending moment, and finally the rotation angle of the double-bead cemented model 8 can be calculated according to the ratio of the difference between two horizontal displacement values measured by the first sensor group and the distance between two linear displacement sensors in the first sensor group.
The bending and shearing combined test operation process comprises the following steps:
the test preparation stage is the same as the compression shear test operation processes 1 and 2;
the height of the loading device and the height of the counter force end lifting platform 12 are adjusted to enable the whole loading device and the counter force end to move in the vertical direction, and the position of a horizontal stepping motor providing horizontal load is kept unchanged, so that the action position of the horizontal load is controlled. During the bending shear combined test, vertical load is acted on the 8 vertical central axes of the two-bead cemented model, a space exists between the action point of the horizontal load output end and the 8 horizontal central axes of the two-bead cemented model, the counter-force end is acted on the 8 horizontal central axes of the two-bead cemented model, the horizontal load output end and the counter-force end generate a pair of horizontal forces with equal size and opposite directions and not on the same straight line, and a bending moment acted on the two-bead cemented model 8 is formed. The double-bead cemented model 8 is damaged under the combined action of a vertical load 14, a horizontal load and a bending moment, and finally the horizontal displacement and the corner of the double-bead cemented model 8 can be calculated according to the measured horizontal displacement and vertical displacement of the L-shaped upper cushion block 5 and the geometric relationship between the L-shaped upper cushion block 5 and the cemented particles 8.
Example 2:
the embodiment discloses a loading device for a double-bead cementing model under complex stress, as shown in fig. 3, a circular arc-shaped groove 21 is formed in a bottom plate 2, and the diameter of the circular arc-shaped groove 21 is consistent with the diameter of a rolling shaft 1 in fig. 2 and the diameter of a circular arc-shaped groove 41 in fig. 5. The roller 1 is placed in the arc-shaped groove 21, and the arc-shaped groove 41 of the L-shaped lower cushion block 4 is matched with the roller 1, so that the L-shaped lower cushion block 4 can rotate around the roller 1.
The round through hole 61 of phi 4 in the connecting piece 6 and the round through hole 524 of phi 4 in the upper rectangular groove 523 of the L-shaped upper cushion block 5 are positioned on the same axis and fixed by a bolt, so that the L-shaped upper cushion block 5 can rotate around the bolt.
Two phi 4 threaded holes 522 are formed in the L-shaped upper cushion block 5 and are used for connecting and fixing two clamping plates 7 (connected through the phi 4 threaded through holes 74). The circular through hole 73 on the clamping plate 7 is used for placing the linear displacement sensor, and the cutting seam 72 is closed by screwing the phi 3 threaded through hole 71 during installation, so that the linear displacement sensor is fixed.
When the double-bead cementing model is used, the double-bead cementing model needs to be installed on double-shaft loading equipment, and mechanical properties of the double-bead cementing model 8 in a complex stress state are tested by loading different vertical loads 14 and horizontal loads 13.
The operation process of the compression-shear test is as follows:
1. placing the prefabricated double-bead cemented model 8 in the arc-shaped groove 41 of the sample cushion block 3, firstly adjusting the double-bead cemented model 8 to be in a vertical state, and smearing a small amount of epoxy resin on the bottom of the double-bead cemented model 8 to bond the bottom of the double-bead cemented model 8 with the sample cushion block 3 so as to keep the vertical state of the double-bead cemented model 8. After the epoxy resin is hardened, the sample cushion block 3 containing the double-bead cementing model 8 is placed in the rectangular groove 43 of the L-shaped lower cushion block 4. And a small amount of epoxy resin is coated on the other sample cushion block 3 arranged in the lower rectangular groove 54 of the L-shaped upper cushion block 5 and the top of the double-bead cementing model 8 to bond the top of the double-bead cementing model 8 with the sample cushion block, and then the upper and lower sample cushion blocks 3 are fixed by screwing bolts at the phi 2 threaded hole 42 and the phi 2 threaded hole 52.
2. The present invention is mounted to a dual axis loading apparatus in the manner shown in fig. 10. The intersection of the vertical part 51 of the L-shaped upper cushion block 5 and the central horizontal axis of the double-bead cemented model 8 bears the horizontal load 13 generated by the stepping motor, and two linear displacement sensors are symmetrically arranged on two sides of the intersection of the horizontal central axis of the double-bead cemented model 8 and the vertical part 51 of the upper cushion block for measuring the horizontal displacement of the L-shaped upper cushion block 5. Similarly, the intersection of the horizontal part 52 of the L-shaped upper cushion block 5 and the central vertical axis of the double-bead cemented model 8 is subjected to a vertical load 14 generated by another stepping motor, and two linear displacement sensors are arranged at the intersection of the vertical central axis of the double-bead cemented model and the horizontal part of the L-shaped upper cushion block 5, and the two linear displacements are fixed in the clamping plate 7 and used for measuring the vertical displacement of the L-shaped upper cushion block 5. And (4) coating lubricating oil on each contact point, and enabling each part to be in good contact.
3. As shown in fig. 10, the two-bead bond model 8 is first placed in an upright position by applying a constant vertical load 14, and then a horizontal load 13 is applied. And displacement control is used during horizontal loading, and the loading rate is set according to the requirements of the test. The double-bead cemented model 8 is damaged under the combined action of the horizontal load 13 and the vertical load 14, two horizontal displacement values are measured by the first sensor group, and the horizontal displacement value of the double-bead cemented model can be obtained by calculating the arithmetic mean value of the two horizontal displacement values.
The operation process of the bending test is as follows:
the test preparation stage is the same as the compression shear test operation processes 1 and 2;
the connecting piece 6 can move horizontally along the linear guide rail 9 to drive the whole loading device to move horizontally, and the position of a vertical stepping motor for providing vertical load is kept unchanged, so that the action position of the vertical load 14 is controlled. During a bending test, an eccentric distance exists between the vertical central axis of the double-bead cementing model 8 and the vertical load 14, so that a bending moment is generated, and no horizontal load 13 is applied in the test, namely no shearing force is generated. The double-bead cemented model 8 is damaged under the combined action of the vertical load 14 and the bending moment, and finally the rotation angle of the double-bead cemented model 8 can be calculated according to the ratio of the difference between two horizontal displacement values measured by the first sensor group and the distance between two linear displacement sensors in the first sensor group.
The bending and shearing combined test operation process comprises the following steps:
the test preparation stage is the same as the compression shear test operation processes 1 and 2;
the height of the loading device and the height of the counter force end lifting platform 12 are adjusted to enable the whole loading device and the counter force end to move in the vertical direction, and the position of a horizontal stepping motor providing horizontal load is kept unchanged, so that the action position of the horizontal load is controlled. During the bending shear combined test, vertical load is acted on the 8 vertical central axes of the two-bead cemented model, a space exists between the action point of the horizontal load output end and the 8 horizontal central axes of the two-bead cemented model, the counter-force end is acted on the 8 horizontal central axes of the two-bead cemented model, the horizontal load output end and the counter-force end generate a pair of horizontal forces with equal size and opposite directions and not on the same straight line, and a bending moment acted on the two-bead cemented model 8 is formed. The double-bead cemented model 8 is damaged under the combined action of a vertical load 14, a horizontal load and a bending moment, and finally the horizontal displacement and the corner of the double-bead cemented model 8 can be calculated according to the measured horizontal displacement and vertical displacement of the L-shaped upper cushion block 5 and the geometric relationship between the L-shaped upper cushion block 5 and the cemented particles 8.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.
Claims (7)
1. A loading device of a double-bead cementing model under complex stress is characterized in that the loading device is arranged on double-shaft loading equipment and comprises a bottom plate, a rolling shaft, a sample cushion block, a lower cushion block, an upper cushion block, first sensor groups symmetrically arranged and used for measuring vertical displacement, second sensor groups symmetrically arranged and used for measuring horizontal displacement and a connecting piece;
the bottom plate is horizontally placed on a horizontally movable base of the double-shaft loading equipment, and a first groove for mounting and positioning the rolling shaft is formed in the bottom plate; the rolling shaft is arranged on the bottom plate and is positioned in the first groove; the lower cushion block is arranged on the roller, the bottom of the lower cushion block is provided with a second groove matched with the roller in a positioning way, the top of the lower cushion block is provided with a third groove used for installing a sample cushion block, and the end part of the lower cushion block is connected with the horizontal load counter-force end; the upper cushion block is arranged above the lower cushion block, the top of the upper cushion block is provided with a fourth groove used for being connected with the connecting piece, the bottom of the upper cushion block is provided with a fifth groove used for installing the sample cushion block, and the end part of the upper cushion block is connected with the horizontal load output end; the sample cushion blocks are respectively arranged in the third groove and the fifth groove and are respectively fixedly connected with the lower cushion block and the upper cushion block; the first sensor group is arranged on the upper cushion block; one end of the connecting piece is inserted into the fourth groove and hinged with the upper cushion block, and the other end of the connecting piece is connected with the linear guide rail end; the double-bead cementing model is arranged between the upper cushion block and the lower cushion block and is respectively fixedly connected with the sample cushion blocks on the upper cushion block and the lower cushion block; the roller, the sample cushion block and the connecting piece are coaxially arranged.
2. The loading device for a dual bead bond model under complex stress of claim 1, further comprising a clamp plate for fixedly mounting the first sensor set; the clamping plate is designed to be of an L-shaped structure, and is provided with a mounting hole for clamping the first sensor group, a cutting seam convenient to mount and a fixing hole; the mounting hole vertically penetrates through the clamping plate; the cutting seam extends from the edge of the clamping plate to the mounting hole and penetrates through the clamping plate; the fixing hole is arranged on the side surface of the clamping plate, and the axis of the fixing hole is perpendicular to the cutting seam and penetrates through the cutting seam.
3. The loading device for the double-bead bond model under the complex stress of claim 1, further comprising a second sensor group for measuring the horizontal displacement of the upper cushion block; the second sensor group adopts two linear displacement sensors, is arranged on the upper cushion block and is fixedly connected with the upper cushion block.
4. The loading device for the double-bead cementing model under the complex stress of claim 1 is characterized in that the upper part of the connecting piece is of a cylindrical structure and is connected with the end of the linear guide rail, and the lower part of the connecting piece is provided with a horizontally arranged through hole hinged with the upper cushion block.
5. The loading device for the double-bead cementing model under the complex stress of claim 1, is characterized in that the upper cushion block and the lower cushion block are both designed in an L-shaped structure, the vertical section of the upper cushion block is connected with the horizontal load output end, and the vertical section of the lower cushion block is connected with the horizontal load counter-force end.
6. The loading device for the double-bead bond model under the complex stress of claim 1, wherein the first sensor set adopts two linear displacement sensors.
7. The loading device for the double-bead cementing model under the complex stress according to claim 1, is characterized in that the first groove and the second groove are designed by adopting an arc-shaped groove structure, and the diameters of the first recess and the second recess are consistent with the diameter of the roller; and the third groove, the fourth groove and the fifth groove are all designed by adopting a cuboid groove structure.
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| CN202010038216.2A CN111077021A (en) | 2020-01-14 | 2020-01-14 | Loading device of double-bead cementing model under complex stress |
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|---|---|---|---|---|
| US20160069182A1 (en) * | 2014-09-10 | 2016-03-10 | Fracture ID, Inc. | Apparatus and method using measurements taken while drilling to map mechanical boundaries and mechanical rock properties along a borehole |
| CN211602708U (en) * | 2020-01-14 | 2020-09-29 | 广东工业大学 | Loading device of double-bead cementing model under complex stress |
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2020
- 2020-01-14 CN CN202010038216.2A patent/CN111077021A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160069182A1 (en) * | 2014-09-10 | 2016-03-10 | Fracture ID, Inc. | Apparatus and method using measurements taken while drilling to map mechanical boundaries and mechanical rock properties along a borehole |
| CN211602708U (en) * | 2020-01-14 | 2020-09-29 | 广东工业大学 | Loading device of double-bead cementing model under complex stress |
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| Title |
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| WANYING WANG，ET AL.: "The Development of a Micromechanical Apparatus Applying Combined Normal Shear-Bending Forces to Natural Sand Grains with Artificial Bonds", 《GEOTECHNICAL TESTING JOURNAL》, vol. 42, no. 4, 20 September 2018 (2018-09-20), pages 1090 - 1099 * |
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