CN107907098A - Complexes and its implementation for the test of soil body three dimensional strain - Google Patents

Abstract

The invention provides a complete set of equipment for three-dimensional strain testing of soil, which includes a three-dimensional strain rosette, a data wire, and a cylindrical rod-shaped placement device. At the same time, it provides an implementation method of a complete set of equipment for soil three-dimensional strain testing. The beneficial effect of the present invention is that the three-dimensional strained soil block can be put into the point to be measured at an inherent angle and depth, which improves the accuracy of the test result and has an irreplaceable role in analyzing the stability of the soil after being stressed and evaluating the safety level of the project. effect. Through actual measurement and comparison, this type of device can improve the test accuracy of the three-dimensional strain device by 79% to 85%. Therefore, this implementation method has very important practical significance and engineering application value.

Description

Complete set of equipment for three-dimensional strain testing of soil and its implementation method

technical field

The invention belongs to the field of soil strain testing in geotechnical engineering, and relates to a complete set of equipment for soil three-dimensional strain testing and an implementation method thereof, which can be used to detect the deformation of the side wall of the foundation pit and the bottom of the foundation pit in foundation pit engineering, and To test the deformation of a point in the soil caused by the added stress.

Background technique

When the external load of the soil changes, the relative positional relationship inside the soil will also change, and we usually call this change in relative position strain. The strain measurement of soil is a basic work in engineering, which plays a very important role in calculating and analyzing the deformation characteristics of soil and evaluating the safety level of soil engineering. Soil deformation has a great impact on the stability of engineering structures, such as: the impact of soil seepage deformation on the safety of embankment projects, the impact of bank slope soil deformation on port wharves, and the impact of upper load conditions on underground tunnel excavation Wait. Therefore, measuring the general strain state, principal strain and shear strain of the soil has very important practical significance for the defense of engineering disasters.

Patent 201410740140.2, Patent 201610917550.9 and Patent 201610964552.3 all disclose a device and testing method for testing the three-dimensional strain state inside the soil. During the implementation process, it was found that the test device and method provided by the device cannot determine the embedding depth and angle of the three-dimensional strain device, so that the actual strain of the soil cannot be obtained. At the same time, the embedding angle and position of the three-dimensional strain device are closely related to its calculation accuracy, so there is an urgent need for a complete set of devices for three-dimensional strain testing of soil and its implementation method, which is conducive to the realization of the application of three-dimensional strain rosettes in undisturbed soil. important role.

Contents of the invention

The purpose of the present invention is to provide a complete set of equipment for three-dimensional strain testing of soil and its implementation method, which can be used in a complete set of three-dimensional strain testing of soil. The device has the advantages of simple operation and effective testing of soil strain.

In order to achieve the above object, the present invention provides a complete set of equipment for three-dimensional strain testing of soil, wherein: the device includes: three-dimensional strain rosettes, data wires, strain rosette manufacturing boxes, and guide rods.

At the same time, it provides an implementation method of a complete set of equipment for soil three-dimensional strain testing.

The invention solves the problem that the three-dimensional soil strain test device is difficult to apply in the undisturbed soil, and the soil strain is tested through the complete set of soil strain test device and its implementation method, which is useful for analyzing the stability of the soil after stress and evaluating engineering The security level plays an irreplaceable role. Through actual measurement and comparison, this type of device can improve the test accuracy of the three-dimensional strain device by 79% to 85%. Therefore, the implementation method of a complete set of equipment for soil three-dimensional strain testing of the present invention has very important practical significance and engineering application value.

Description of drawings

Fig. 1 schematic diagram of the box for making rosettes involved in the present invention;

Fig. 2 schematic diagram of the three-dimensional strained soil block involved in the present invention;

Fig. 3 is a schematic structural view of the chuck of the placement device of the present invention;

Fig. 4 is a structural schematic diagram of the outer cylinder and the outer cylinder cap of the placement device of the present invention;

Fig. 5 is a structural schematic diagram of the inner rod and the nut of the placement device of the present invention;

Fig. 6 is a structural schematic diagram of the placement device of the present invention;

Fig. 7 is a front view of placing three-dimensional strained soil blocks by using the placement device of the present invention;

Fig. 8 is a top view of placing three-dimensional strained soil blocks by using the placing device of the present invention.

In the picture:

1. Three-dimensional rosette 2. Data wire 3. Rosette making box 4. Guide rod

5. Three-dimensional strained soil block 41. Chuck 42. Inner rod 43. Outer cylinder

44. Outer cylinder cap 45. Nut 46. Thread 47. Thread groove

411. Spring 441. Round hole

Detailed ways

The complete device for soil three-dimensional strain test and its implementation method of the present invention will be described in conjunction with the accompanying drawings.

The design idea of the present invention is how to put the three-dimensional strain rosette into the test point at a specified test angle, and keep the shape of the three-dimensional strain rosette unchanged. Based on the idea that the manufacturing accuracy of small samples is easy to control, the three-dimensional strain rosette 1 is placed in the rosette production box 3, and the gap between the strain rosette production box 3 and the three-dimensional strain rosette 1 is filled with soil to form a three-dimensional strain gauge. Soil block 5, as shown in Figure 2. Then use the placement device to put the three-dimensional strained soil block 5 into the test point.

For this reason, the structure of the complete set of devices used for soil three-dimensional strain testing of the present invention is that the complete set of devices is connected with the strain collection box, the complete set of devices includes a test device and a placement device, and the test device includes a three-dimensional strain rosette 1, Data wire 2, strain rosette making box 3, described strain rosette making box 3 is the shape of a cube without a cover whose length, width and height are 15cm, the three-dimensional strain rosette 1 is placed in the strain rosette making box 3, and the strain rosette making box 3 The gap between the three-dimensional strain rosette 1 is filled with the soil body, that is, a three-dimensional strain soil block 5 is formed, and the multiple strain rod wires of the three-dimensional strain rosette 1 are aggregated into one data wire 2, and the data wire 2 is connected to the strain collection box. The joints are connected to form a test device; the guide rod 4 is the placement device; the chuck 41 of the guide rod 4 clamps the three-dimensional strained soil block 5 to form a complete set of devices. As shown in Figure 1.

Put the three-dimensional strain rosette 1 into the strain rosette making box 3, and fill the gap between the strain rosette making box 3 and the three-dimensional strain rosette 1 with soil to form a three-dimensional strained soil block 5, and the data wire 2 and the three-dimensional strained soil Block 5 is connected as shown in Figure 2. The guide rod 4 includes: a collet 41, an inner rod 42, an outer cylinder 43, an outer cylinder cap 44, and a nut 45, as shown in FIG. 6 . The upper end of the inner rod 42 is provided with a thread 46 , and the lower end of the inner rod 42 is provided with a thread groove 47 , as shown in FIG. 5 . The upper end of the outer cylinder 43 is provided with a screw thread 46, the lower end of the outer cylinder 43 is provided with a thread groove 47, the outer cylinder cap 44 is cap-shaped and the inner wall is provided with a thread groove 47, and the top of the outer cylinder cap 44 is provided with a circular hole 441, As shown in Figure 4. The upper end of the chuck 41 is provided with a thread 46, and a spring 411 is installed at the joint of the chuck 41, as shown in FIG. 3 . Connect the thread 46 at the upper end of the outer cylinder 43 with the thread groove 47 of the outer cylinder cap 44, connect the thread 46 at the tail end of the chuck 41 with the thread groove 47 at the lower end of the inner rod 42, and pass the upper end of the inner rod 42 through the outer cylinder 43 and the round hole 441 of the outer cylinder cap 44, and the nut 45 is connected to the upper end of the inner rod 42 to form the guide rod 4, as shown in FIG. 6 .

Put the three-dimensional strain rosette 1 into the strain rosette making box 3, and fill the space between the strain rosette making box 3 and the three-dimensional strain rosette 1 to form a three-dimensional strain rosette 5; The rod wires are summarized into a data wire 2, and the data wire 2 is connected with the joint of the strain collection box to form a test device; then the guide rod 4 is assembled to form a placement device; Putting it into the point to be measured constitutes a complete set of equipment for three-dimensional strain testing of soil.

The implementation method of the complete set of equipment for soil three-dimensional strain test of the present invention, this implementation method comprises the following steps:

1) Prepare a three-dimensional strained soil block 5, and combine multiple strain rod wires of the three-dimensional strain rosette 1 into one data wire 2, as shown in FIG. 2 .

2) Drill holes in the site to be tested, and prepare for placing the three-dimensional strained soil block 5 in the following steps.

3) Assemble the guide rod 4, as shown in FIG. 6 .

4) Clamp the three-dimensional strained soil block 5 prepared in step 1) by the chuck 41 of the guide rod 4, and then clamp the three-dimensional strained soil block 5 by rotating the nut 45 to prevent the three-dimensional strained soil block 5 from falling off during placement, As shown in Figure 7 and 8.

5) The three-dimensional strained soil block 5 clamped by the guide rod 4 described in step 4) is sent into the borehole of step 2), and the chuck 41 is loosened by rotating the nut 45, so that the three-dimensional strained soil block 5 and the chuck 41 Disconnect to achieve the purpose of putting the three-dimensional strained soil block 5 into the point to be measured, lead the data wire 2 out from the borehole and connect it with the strain collection box, and then fill the surrounding pores with soil.

6) The deformation of the soil at the point to be measured drives the deformation of the three-dimensional strain rosette 1, and the readings collected by the strain collection box are denoted as ε ₁ , ε ₂ , ε ₃ , ε ₄ , ε ₅ , ε ₆ , respectively, through the formula (1) To calculate the three-dimensional strain state of the soil, the formula (1) is as follows:

In the formula: ε ₁ , ε ₂ , ε ₃ , ε ₄ , ε ₅ , ε ₆ are the readings in the direction of the six strain bars of the three-dimensional rosette 1 obtained by the strain collection box; ε _x , ε _y , ε _z , ε _xy , ε _yz , ε _zx are respectively the strain in the x-axis direction, the y-axis direction strain, the z-axis direction strain in the soil, the shear stress direction strain on the xoy plane, the shear stress direction strain on the yoz plane, and the shear stress direction strain on the xoz plane.

The three-dimensional strain rosette 1 is fixed in the three-dimensional strain soil block 5, and the direction cosines l _i , m _i , and _ni (i=1, 2 , 3, 4, 5, 6) are respectively:

n _i = cosδ _i (4)

In the formula, _δi is the angle between the three-dimensional rosette 1 strain rods in the xoy projection and the x-axis, is the angle (i=1, 2, 3, 4, 5, 6) between each strain rod of the three-dimensional rosette 1 and the z-axis. The matrix operator T ^-1 composed of direction cosine l, m, n is as follows:

After the three-dimensional strained soil block 5 is put into the point to be measured in parallel, the spatial position of the three-dimensional strain rosette 1 at the point to be measured is still equal to the spatial position in the three-dimensional strained soil block 5, so the three-dimensional strained rosette 1 is placed in the three-dimensional strained soil block 5. The soil block 5 can effectively determine the embedding angle and embedding position of the three-dimensional rosette 1 in the three-dimensional space. When the spatial position of the three-dimensional rosette 1 changes, that is, δ _i , changes, the matrix operator T ^-1 will also change. From formula (1), the calculated {ε _x , ε _y , ε _z , ε _xy , ε _yz , ε _zx } will change, resulting in inaccurate test results .

Claims (2)

1. a kind of complexes for the test of soil body three dimensional strain, which is connected with strain acquirement case, its feature It is：The complexes include test device, apparatus for placing, and the test device includes three dimensional strain flower (1), data conductor (2), strain rosette makes box (3), and it is uncovered pros shape that length, width and height are 15cm that the strain rosette, which makes box (3), and three Dimension strain rosette (1) inserts strain rosette and makes in box (3), and making the gap between box (3) and three dimensional strain flower (1) in strain rosette fills out The soil body is filled, that is, forms a three dimensional strain soil block (5), more strain bar conducting wires of three dimensional strain flower (1) collect for a single data Conducting wire (2), data conductor (2) are connected with the connector of the strain acquirement case, constitute test device；Guide rod (4) is to place Device；The collet (41) of guide rod (4) clamps three dimensional strain soil block (5) and forms complexes.

The guide rod (4) includes collet (41), interior bar (42), outer barrel (43), outer barrel cap (44), nut (45), interior bar (42) Upper end be provided with screw thread (46), the lower end of interior bar (42) is provided with thread groove (47), and the upper end of outer barrel (43) is provided with screw thread (46), the lower end of outer barrel (43) is provided with thread groove (47), and the outer barrel cap (44) is provided with thread groove for hat shape and inner wall (47), the roof fall of outer barrel cap (44) is provided with circular hole (441), and collet (41) upper end is provided with screw thread (46), and collet (41) junction is equipped with spring (411), by thread groove (47) phase of the screw thread (46) of outer barrel (43) upper end and outer barrel cap (44) Connection, the screw thread (46) of collet (41) tail end is connected with the thread groove (47) of interior bar (42) lower end, by interior bar (42) upper end It is connected through outer barrel (43) and the circular hole (441) of outer barrel cap (44), and by nut (45) with interior bar (42) upper end, that is, forms guide rod (4)。

2. utilize the implementation of the complexes for being used for the test of soil body three dimensional strain described in claim 1, the implementation Comprise the following steps：

1) the three dimensional strain soil block (5) described in claim 1 is prepared, the more strain bar conducting wires that three dimensional strain spends (1) are collected For a single data conducting wire (2)；

2) drill in place to be measured, be to be put into three dimensional strain soil block (5) in following step to be ready；

3) guide rod (4) is assembled；

4) step 1) is clamped by the collet (41) of guide rod (4) and prepares the three dimensional strain soil block (5) formed, then pass through rotary nut (45) three dimensional strain soil block (5) is clamped, prevents three dimensional strain soil block (5) from coming off in placement process；

5) the three dimensional strain soil block (5) for clamping the guide rod (4) described in step 4) is sent into the drilling of step 2), passes through rotary nut (45) collet (41) is unclamped, three dimensional strain soil block (5) is disconnected with collet (41), three dimensional strain soil block (5) is put into and is treated Measuring point, data conductor (2) is exported from drilling and is connected with the connector of strain acquirement case, is then filled out hole around with the soil body Fill closely knit；

6) deformation that the tested point soil body produces drives three dimensional strain flower (1) deformation, and the reading collected by strain acquirement case, point ε is not denoted as it₁、ε₂、ε₃、ε₄、ε₅、ε₆, it is as follows by the three dimensional strain state of formula (1) the calculating soil body, formula (1)：

<mrow> <mfenced open = "{" close = "}"> <mtable> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mi>x</mi> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mi>y</mi> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mi>z</mi> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mrow> <mi>x</mi> <mi>y</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mrow> <mi>y</mi> <mi>z</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mrow> <mi>z</mi> <mi>x</mi> </mrow> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>=</mo> <mfenced open = "{" close = "}"> <mtable> <mtr> <mtd> <mn>1</mn> </mtd> <mtd> <mn>0</mn> </mtd> <mtd> <mn>0</mn> </mtd> <mtd> <mn>0</mn> </mtd> <mtd> <mn>0</mn> </mtd> <mtd> <mn>0</mn> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>-</mo> <mn>0.333</mn> </mrow> </mtd> <mtd> <mn>0.667</mn> </mtd> <mtd> <mn>0</mn> </mtd> <mtd> <mn>0.667</mn> </mtd> <mtd> <mn>0</mn> </mtd> <mtd> <mn>0</mn> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>-</mo> <mn>0.839</mn> </mrow> </mtd> <mtd> <mn>0.176</mn> </mtd> <mtd> <mn>1.502</mn> </mtd> <mtd> <mn>0.176</mn> </mtd> <mtd> <mrow> <mo>-</mo> <mn>1.502</mn> </mrow> </mtd> <mtd> <mn>1.502</mn> </mtd> </mtr> <mtr> <mtd> <mn>0</mn> </mtd> <mtd> <mn>1.155</mn> </mtd> <mtd> <mn>0</mn> </mtd> <mtd> <mrow> <mo>-</mo> <mn>1.115</mn> </mrow> </mtd> <mtd> <mn>0</mn> </mtd> <mtd> <mn>0</mn> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>-</mo> <mn>1.427</mn> </mrow> </mtd> <mtd> <mn>0.735</mn> </mtd> <mtd> <mn>2.119</mn> </mtd> <mtd> <mn>0.735</mn> </mtd> <mtd> <mrow> <mo>-</mo> <mn>4.237</mn> </mrow> </mtd> <mtd> <mn>2.119</mn> </mtd> </mtr> <mtr> <mtd> <mn>0</mn> </mtd> <mtd> <mn>0.410</mn> </mtd> <mtd> <mrow> <mo>-</mo> <mn>1.226</mn> </mrow> </mtd> <mtd> <mrow> <mo>-</mo> <mn>0.410</mn> </mrow> </mtd> <mtd> <mn>0</mn> </mtd> <mtd> <mn>1.226</mn> </mtd> </mtr> </mtable> </mfenced> <mfenced open = "{" close = "}"> <mtable> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mn>1</mn> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mn>2</mn> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mn>3</mn> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mn>4</mn> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mn>5</mn> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&amp;epsiv;</mi> <mn>6</mn> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow>

In formula：ε₁、ε₂、ε₃、ε₄、ε₅、ε₆The reading on 6 strain bar directions of (1) is spent for strain acquirement case；ε_x、ε_y、ε_z、 ε_xy、ε_yz、ε_zxX-axis direction strains respectively in the soil body；Y-axis direction strains；Z-axis direction strains；Shear stress direction should on xoy faces Become；Shear stress direction strains on yoz faces；Shear stress direction strains on x oz faces；

By three dimensional strain soil block 5 it is parallel be put into tested point after, three dimensional strain spends 1 to be still equal in the locus of tested point Locus in three dimensional strain soil block 5, therefore three can effectively be determined by spending 1 to be placed in three dimensional strain soil block 5 three dimensional strain Tie up the embedded angle in three dimensions of strain rosette 1 and burial place.