CN107621524B - Transparent soil model test device and test method for simulating tunnel excavation deformation - Google Patents

Abstract

The invention provides a transparent soil model test device and a transparent soil model test method for simulating tunnel excavation deformation. The apparatus includes a transparent mold box that can be fixed to an optical platform, as well as a thin-walled rubber cylinder and a drain. The transparent model box is spliced into a box body by plates. The two side walls of the box body are provided with circular openings. And an opening is formed in the edge of the bottom surface of one side of the thin-wall rubber cylinder. The thin-walled rubber cylinder passes through an opening in the transparent mold box. And the drain pipe is provided with a valve. The drain pipe is connected to an opening on the thin-wall rubber cylinder. Two industrial cameras and two laser transmitters are arranged outside the transparent model box. During the test, the valve on the drain pipe is opened, and the water in the thin-wall rubber cylinder is drained into a graduated beaker in a graded manner. The two laser transmitters emit laser to form two transparent soil speckle fields in the transparent soil. The industrial camera records changes in the transparent soil speckle field.

Description

A transparent soil model test device and test method for simulating tunnel excavation deformation

technical field

The invention relates to the technical field of visualization tests of tunnels and underground engineering, in particular to a transparent soil model test device and a test method for simulating tunnel excavation deformation.

Background technique

With the rapid development of the economy, my country's tunnel projects have obtained unprecedented development opportunities, including road tunnels, railway tunnels, hydraulic tunnels, urban subways and other tunnel projects. However, with the rapid development of tunnel engineering, many challenges will also appear; among them, the deformation and damage of tunnel engineering during the construction process is one of the issues that engineers are very concerned about.

The deformation and failure of tunnels is a three-dimensional problem with very complex properties of surrounding rock, external loads and boundary conditions. At present, mathematical mechanics methods can only provide analytical solutions for some tunnel projects with simple shapes and simplified boundary conditions, and the analytical solutions obtained are still It is inseparable from the verification of field measured data and model tests. Many analytical conclusions come from field measurements, numerical analysis and model tests. Among them, because the model test is a physical model entity, it can not only reflect the changes of the stress field and displacement field in the actual working conditions more realistically and intuitively under the premise of satisfying the similarity principle, but also avoid complex mathematical and mechanical derivations. It is easier for engineers to fully grasp the overall deformation and stability characteristics of geotechnical engineering.

The traditional indoor model test can only observe the macroscopic deformation of the model and the change law of the boundary area, but the deformation characteristics inside the model cannot be directly observed. The transparent soil test technology can realize the visualization of the three-dimensional deformation and strength of the model, which provides an effective technical support for the study of the deformation law and failure mechanism of the surrounding rock caused by tunnel excavation.

The synthetic transparent soil material has physical and mechanical properties similar to real soil, and has good transparency. PIV technology can accurately measure the displacement field of soil. Tunnel model tests based on transparent soil experimental materials help us to fully understand the development law of tunnel excavation deformation, and provide a reliable scientific basis for optimizing tunnel design and construction schemes.

Contents of the invention

The object of the present invention is to provide a kind of transparent soil model test device for simulating tunnel excavation deformation, it is characterized in that:

It mainly includes transparent model box, rubber thin-walled round pipe, drain pipe, industrial camera I, industrial camera II, laser emitter I, laser emitter II and optical table.

The transparent model box is a hollow cuboid made of transparent material, its upper end is open, and its four sides are respectively defined as front, rear, left and right sides. The lower end of the transparent model box rests on the optical platform. There are circular openings I and circular openings II on the front and rear sides of the transparent model box respectively.

The rubber thin-walled circular tube is a water-filled rubber tube. The two ends of the thin-walled rubber tube are embedded in the circular opening I and the circular opening II respectively.

The end surface of the rubber thin-walled circular tube embedded in the front side of the transparent model box has a circular opening for connecting a drain pipe. The drain pipe has a valve.

The space inside the transparent model box can be used to fill the transparent soil.

The supporting frame of the laser emitter I and the laser emitter II is installed on the optical platform, and its height and horizontal position are adjustable. The laser emitter I and the laser emitter II emit laser light to the rear side and the right side of the transparent model box.

The supporting frame of the industrial camera I and the industrial camera II is installed on the optical platform, and its height and horizontal position are adjustable. The industrial camera I and the industrial camera II photograph the top surface and the left side of the transparent model box respectively.

Further, the transparent model box is made of plexiglass. The left and right side panels and the bottom panel are glued together. The front and rear side panels where the circular opening I and the circular opening II are located are connected to the left and right side panels and the base plate by bolts. The side panels are removable.

Further, the circular opening I and the circular opening II simulate tunnel holes. The position of the tunnel hole simulated by the rubber thin-walled circular tube, the positions of the circular opening I and the circular opening II can be designed according to different working conditions in order to meet the test requirements.

Further, water-stop strips are pasted between the joints of the panels at the bolted joints to prevent the seepage of liquid in the transparent soil.

Further, the outer diameter of the thin-walled rubber cylinder, the diameter of the circular opening I and the diameter of the circular opening II are the same.

The length of the thin-walled rubber cylinder is the same as the length between the front and rear panel outer walls of the transparent model box.

The present invention also discloses a test method using the above-mentioned test device, which is characterized in that it comprises the following steps:

1) Make a transparent model box, a thin-walled rubber cylinder and a drainage pipe according to the designed size.

2) Fill the thin-walled rubber cylinder with water, and place it upside down so that the bottom of the hole is facing upward.

3) Connect the thin-walled rubber cylinder to the drain pipe, and do waterproof sealing on the connection.

4) Put the thin-walled rubber cylinder through the opening of the transparent model box, place it in the box, and do waterproof sealing for the interface.

5) Prepare the transparent soil in the transparent model box to the design height. Let stand for 24 hours after preparation.

6) Arrange and adjust industrial cameras and laser transmitters.

7) Control the valve on the drain pipe to discharge the water in the thin-walled rubber round pipe one by one. After the water in the thin-walled rubber tube is discharged each time, the speckle field in the transparent soil is stabilized, and an industrial camera is used to take pictures. Adjust the horizontal position and height of the laser transmitter to obtain images of the transparent soil section at different positions after the i-time drainage. Until the water in the thin-walled rubber tube is completely discharged.

8) Save the picture, turn off the laser transmitter, and sort out the test equipment.

9) Use PIV technology to process the test image to obtain the displacement vector diagram of each section of transparent soil.

7. A kind of test method according to claim 6, characterized in that: after step 1), there is also a related step of scrubbing the side wall of the transparent model box.

The present invention overcomes the shortcomings of traditional tunnel model tests that can only obtain macroscopic deformation and boundary area deformation, and its technical effect is beyond doubt:

A) Visual measurement of soil deformation around the tunnel can be realized, and non-intrusive measurement can be performed on the development and change of the soil displacement field around the tunnel during the simulated excavation process;

B) The real three-dimensional displacement field of the soil deformation around the tunnel can be obtained by measuring the displacement field of the multi-section soil;

C) The excavation process can be simulated by controlling the displacement;

D) The model box is assembled from three parts, and the required working conditions can be set according to the test requirements without repeated processing. The size of the test device is small, the system setting is reasonable, and the test operation is convenient.

Description of drawings

Fig. 1 is a schematic structural diagram of a transparent model box;

Fig. 2 is a schematic diagram of a rubber thin-walled cylinder;

Fig. 3 is a schematic diagram of a drainage pipe;

Figure 4 is a schematic diagram of the laser plane during the test;

Figure 5 is a schematic diagram of the test device structure.

In the figure: transparent model box 1, circular opening I101, circular opening II102, transparent soil 2, rubber thin-walled circular tube 3, circular opening 301, drain pipe 4, valve 401, industrial camera I5, industrial camera II50, Laser transmitter I6, laser transmitter II60, optical platform 7.

Detailed ways

The present invention will be further described below in conjunction with the examples, but it should not be understood that the scope of the subject of the present invention is limited to the following examples. Without departing from the above-mentioned technical ideas of the present invention, various replacements and changes made according to common technical knowledge and conventional means in this field shall be included in the protection scope of the present invention.

Example 1:

A transparent soil model test device for simulating tunnel excavation deformation, characterized in that:

It mainly includes transparent model box 1, rubber thin-walled round pipe 3, drain pipe 4, industrial camera I5, industrial camera II50, laser emitter I6, laser emitter II60 and optical platform 7.

Referring to Fig. 1, the transparent model box 1 is spliced into a whole by panels, made of plexiglass, its upper end is open, and its four sides are respectively defined as front, rear, left and right sides [This definition is for the convenience of description, expressing the positional relationship of the four surfaces]. The transparent model box 1 is made of plexiglass. The left and right side panels and the bottom panel are glued together. The two side panels where the circular opening I101 and the circular opening II102 are located are connected to the left and right side panels and the bottom plate by bolts. The side panels are removable. Waterstop strips are attached to the joints of the bolted joints between the panels to prevent the liquid in the transparent soil 2 from seeping out.

The lower end of the transparent model box 1 rests on the optical platform 7 . There are circular openings I101 and circular openings II102 on the front and rear sides of the transparent model box 1 respectively.

Referring to Fig. 5 and Fig. 2, the rubber thin-walled circular tube 3 is a rubber tube filled with water. The two ends of the thin-walled rubber tube 3 are embedded in the circular opening I101 and the circular opening II102 respectively. Circular opening I101, circular opening II102 and rubber thin-walled circular tube 3 simulate tunnel holes. The positions of the simulated tunnel holes, that is, the positions of the circular opening I101 and the circular opening II102 can be designed according to different working conditions in order to meet the test requirements. The outer diameter of the thin-walled rubber cylinder 3, the diameter of the circular opening I101 and the diameter of the circular opening II102 are the same. The length of the thin-walled rubber cylinder 3 is the same as the length between the front and rear panel outer walls of the transparent model box 1 .

Referring to FIG. 4 , the end surface of the thin-walled rubber tube 3 near the front side of the transparent model box 1 has a circular opening 301 for connecting the drain pipe 4 . The drain pipe 4 has a valve 401 .

The space inside the transparent model box 1 can be used to fill the transparent soil 2 .

The supporting frames of the laser emitter I6 and the laser emitter II60 are installed on the optical table 7, and their height and horizontal position are adjustable. The laser emitter I6 and the laser emitter II60 emit laser light to the rear side and the right side of the transparent model box 1 .

The supporting frames of the industrial camera I5 and the industrial camera II50 are installed on the optical table 7, and their height and horizontal position are adjustable. The industrial camera I5 and the industrial camera II50 photograph the top surface and the left side of the transparent model box 1 respectively. The optical table 7 is provided with reserved screw holes. The bracket is fixed on the optical platform 7 by bolts.

During the test, the thin-walled rubber cylinder 3 was filled with water. The thin-walled rubber cylinder 3 passes through the opening 101 and is placed in the transparent mold box 1 before the transparent soil 2 is configured. The water in the thin-walled rubber cylinder 3 is discharged through the valve 401 on the drain pipe 4 . The two laser emitters 8 emit laser light to irradiate the transparent model box 1 to form vertical and horizontal laser sections, and form two transparent soil speckle fields in the transparent soil 2 in orthogonal directions. The shooting direction of the industrial camera 5 is perpendicular to the laser plane, and records the change of the transparent soil speckle field.

It is worth noting that, by controlling the valve 401 on the drain pipe 4, the amount of drainage can be controlled to simulate the process of tunnel excavation deformation. It is helpful for a more in-depth and intuitive understanding of the deformation of the tunnel during the excavation process. After the deformation of the transparent soil is stabilized, the industrial camera is used to shoot the laser plane, and the real three-dimensional displacement field of the tunnel excavation deformation can be obtained through analysis, which can realize the visual measurement of the tunnel excavation deformation.

Example 2:

This embodiment discloses a test method based on the test device described in Example 1, which is characterized in that it comprises the following steps:

1) Make a transparent model box 1, a thin-walled rubber cylinder 3 and a drain pipe 4 according to the designed size.

2) Fill the thin-walled rubber cylinder 3 with water, and place it upside down so that the bottom surface where the opening 301 is located faces upward.

3) Connect the thin-walled rubber cylinder 3 to the drain pipe 4, and perform waterproof sealing on the joint.

4) Put the thin-walled rubber cylinder 3 through the opening 101 of the transparent model box 1, place it in the box, and perform waterproof sealing on the interface.

5) Prepare the transparent soil 2 in the transparent model box 1 to the design height. Let stand for 24 hours after preparation. In the embodiment, the preparation method of the transparent soil 2 is as follows: pour the prepared mixed solution of white oil and n-dodecane into the transparent model box 1 . Afterwards, fused silica sand solid particles with a particle size of 0.1-0.5 mm are spread. The fused silica sand particles are spread in layers, each layer is 30mm thick, and the spreading process should be slow. After spreading one layer, stir the transparent soil to draw out the air bubbles mixed in it, so as to prevent the air bubbles from affecting the refractive index of the transparent soil, until the distance between the liquid surface of the transparent soil The upper edge of the transparent model box 1 is 30mm.

6) Arrange and adjust the industrial camera 5 and the laser emitter 6 so that the two laser emitters 6 emit laser light to irradiate the transparent model box 1 to form a vertical plane and a horizontal laser section, and form two orthogonal directions in the transparent soil 2. Transparent soil speckle field. Arrange the industrial camera 5 so that the shooting direction of the industrial camera 5 is perpendicular to the laser plane to obtain an optimal viewing angle.

7) Turn off the laboratory lighting source, and open the valve 401 on the drain pipe 4 . In this embodiment, the water in the rubber thin-walled circular tube 3 is discharged in stages. Drain the water into a graduated beaker, controlling the same amount of water each time. After each drainage is completed, the speckle field in the transparent soil 2 is stabilized, and the industrial camera 5 is used to take pictures. It is also necessary to adjust the position of the laser transmitter 6 under the premise of ensuring that the two laser transmitters are positioned on different planes and vertically, so as to obtain speckle images of different positions inside the transparent soil 2 soil under this level of displacement, until each drainage is completed .

8) Save the picture, turn off the laser transmitter 6, and sort out the test equipment.

9) Use PIV technology to process the test images to obtain the displacement vector diagram of each section of the transparent soil 2 soil during the tunnel excavation deformation process, and to obtain the three-dimensional displacement field of the tunnel deformation with different displacements through multiple tests.

Claims (4)

1. a test method of a transparent soil model test device for simulating tunnel excavation deformation, is characterized in that, comprises the following steps: 1) Make a transparent model box (1), a thin-walled rubber cylinder (3) and a drainpipe (4) according to the designed size, wherein the transparent model box (1) is a hollow cuboid made of transparent material, and its upper end is open mouth, its four sides are respectively defined as the front, rear, left and right sides; the lower end of the transparent model box (1) rests on the optical platform (7); the front and rear sides of the transparent model box (1) There are respectively circular opening I (101) and circular opening II (102) on the side; the front and rear side panels where the circular opening I (101) and circular opening II (102) are located are connected by bolts On the left and right side panels and the bottom plate; these two side panels can be disassembled; the circular opening I (101), the circular opening II (102) and the rubber thin-walled circular tube (3) simulate the tunnel hole; the simulated tunnel hole The position of the circular opening I (101) and the circular opening II (102) can be designed according to different working conditions in order to meet the test requirements; The rubber thin-walled circular tube (3) is a water-filled rubber tube; the two ends of the rubber thin-walled circular tube (3) are respectively embedded in a circular opening I (101) and a circular opening II (102); The end face of the rubber thin-walled round pipe (3) near the front side of the transparent model box (1) has a circular opening (301) for connecting the drain pipe (4); the drain pipe (4) has a valve (401) ; The space inside the transparent model box (1) can be used to fill the transparent soil (2); 2) Fill the thin-walled rubber cylinder (3) with water and place it upside down with the opening (301) facing up; 3) Connect the thin-walled rubber cylinder (3) to the drain pipe (4), and perform waterproof sealing on the joint; 4) Put the thin-walled rubber cylinder (3) through the opening (101) of the transparent model box (1), place it in the box, and perform waterproof sealing on the interface; 5) Prepare the transparent soil (2) in the transparent model box (1) to the design height; after the preparation is completed, let it stand for 24 hours; the preparation method of the transparent soil (2) is: pour it into the transparent model box (1) Prepared mixture of white oil and n-dodecane; then spread fused silica sand solid particles with a particle size of 0.1 to 0.5mm; fused silica sand particles are spread in layers, each layer thickness is 30mm, the spreading process should be slow, spread once After layering, stir the transparent soil to draw out the air bubbles mixed therein, so as to prevent the air bubbles from affecting the refractive index of the transparent soil until the liquid surface of the transparent soil is 30 mm from the upper edge of the transparent model box (1); 6) arrange and adjust industrial camera (5) and laser emitter (6); The support frame of described laser emitter I (6) and laser emitter II (60) is installed on the optical platform (7), and its height and The horizontal position is adjustable; the laser emitter I (6) and the laser emitter II (60) emit laser light to the rear side and the right side of the transparent model box (1); The supporting frame of described industrial camera I (5) and industrial camera II (50) is installed on the optical platform (7), and its height and horizontal position are adjustable; Described industrial camera I (5) and industrial camera II (50) Photograph the top surface and the left side of the transparent model box (1) respectively; 7) Control the valve (401) on the drainpipe (4) to discharge the water in the thin-walled rubber round pipe (3) several times; 2) The medium speckle field is stable, and the industrial camera (5) is used for shooting; the horizontal position and height of the laser emitter (6) are adjusted to obtain images of transparent soil sections at different positions after the i-time drainage; until the thin wall The water in the rubber tube (3) is all discharged; 8) Save the picture, turn off the laser transmitter (6), and organize the test equipment; 9) Use PIV technology to process the test image to obtain the displacement vector diagram of each section of the transparent soil (2). 2. the test method of a kind of transparent soil model test device for simulating tunnel excavation deformation according to claim 1, is characterized in that: after step 1), also has the relevant step of scrubbing transparent model case (1) side wall . 3. the test method of a kind of transparent soil model test device for simulating tunnel excavation deformation according to claim 1, is characterized in that: stick water-stop strip between the panel seam of bolt joint, to prevent transparent soil (2) Fluid leaks out. 4. according to claim 1 and 3 described a kind of test method of the transparent soil model test device of simulation tunnel excavation deformation, it is characterized in that: described thin-walled rubber cylinder (3) outer diameter, circular opening 1 The diameter of (101) is identical with the diameter of circular opening II (102); The length of the thin-walled rubber cylinder (3) is the same as the length between the front and rear panel outer walls of the transparent model box (1).

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