Device and method for simulating long-term interaction between surrounding rock and lining of operating tunnels

Abstract

The present invention discloses a long-term interaction simulation test device and method for surrounding rock and lining of an operating tunnel, which belongs to the research field of long-term operation and maintenance safety control technology of tunnels and underground projects, and includes a model test box and a constant pressure loading device, wherein the constant pressure loading device includes a loading frame and a force applying mechanism, the model test box is located in the loading frame, the force applying mechanism includes an upper force applying mechanism and a side force applying mechanism, the upper force applying mechanism includes an upper elevator, a first screw and an upper pressure plate, the upper elevator is connected to the first screw, and the end of the first screw is connected to the upper pressure plate; the side force applying mechanism includes a side elevator, a second screw and a side pressure plate, the side elevator is connected to the second screw, and the end of the second screw is connected to the side pressure plate. The device can simulate different surrounding rock characteristics and ground stress characteristics, fully consider the timeliness law of surrounding rock and lining interaction changes, and more realistically reflect the stress and deformation changes of tunnel surrounding rock and lining structure under long-term loading conditions.

Description

Technical Field

[0001] The present invention belongs to the research field of long-term operation and maintenance safety control theory and technology of tunnels and underground projects, and specifically relates to a simulation test device and method for long-term interaction between surrounding rock and lining of an operating tunnel. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the increase in the scale and number of tunnel and underground engineering construction, a large number of tunnels have been put into operation in the fields of highways, railways, municipal engineering, etc. During the operation of the tunnel, there is a complex interaction mode between the surrounding rock and the lining structure, which becomes a key factor affecting the long-term safety of the tunnel structure. Under the action of environmental loads, the surrounding rock produces a creep effect, which leads to the continuous increase of the surrounding rock pressure on the lining structure, and then the deformation, cracking and even failure of the lining occur. On the other hand, the deformation and damage of the lining structure will affect the stress and deformation state of the surrounding rock, resulting in changes in the interaction mode between the surrounding rock and the lining. Therefore, the study of the interaction mechanism between the surrounding rock and the lining structure under the influence of creep can provide theoretical and technical guidance for the long-term service status judgment and disaster prevention and control of operating tunnels.

[0004] Model testing is an important research method widely used in the field of tunnels and underground engineering, which can provide basic data support for theoretical analysis and numerical simulation. However, most of the existing tunnel model test methods study the surrounding rock and tunnel structure separately, and the study of surrounding rock-lining interaction also lacks consideration of long-term service performance. In addition, the existing tunnel model test equipment has problems such as large size, complex operation, and poor loading flexibility. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a long-term interaction simulation test device and method for the surrounding rock-lining of an operating tunnel. The device can simulate different surrounding rock characteristics and ground stress characteristics, fully consider the timeliness of the changes in the surrounding rock-lining interaction, and more realistically reflect the stress and deformation changes of the tunnel surrounding rock-lining structure under long-term loading conditions.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In the first aspect, the present invention provides a long-term interaction simulation test device for surrounding rock and lining of an operating tunnel, including a model test box and a constant pressure loading device, the constant pressure loading device including a loading frame and a force-applying mechanism, the model test box is located in the loading frame, the force-applying mechanism includes an upper force-applying mechanism and a side force-applying mechanism, the upper force-applying mechanism includes an upper elevator, a first screw and an upper pressure plate, the upper elevator is connected to the first screw to drive its vertical movement, and the end of the first screw is connected to the upper pressure plate; the side force-applying mechanism includes a side elevator, a second screw and a side pressure plate, the side elevator is connected to the second screw to drive its horizontal movement, and the end of the second screw is connected to the side pressure plate.

[0008] As a further technical solution, the upper elevator is fixed to the top of the loading frame.

[0009] As a further technical solution, the side lifter is fixed to the side of the loading frame.

[0010] As a further technical solution, the force measuring mechanism includes an upper sensor, which is fixed between the end of the first lead screw and the upper pressure plate, and is connected to the control unit.

[0011] As a further technical solution, the force measuring mechanism also includes a side sensor, which is fixed between the end of the second screw rod and the side pressure plate, and is connected to the control unit.

[0012] As a further technical solution, the model test box includes a bottom wall, a right side wall, a rear side wall, and a front side wall connected to form a box. The front side wall is fixedly connected to the bottom wall in a detachable manner. The upper pressure plate is arranged on the top of the model test box, and the side pressure plate is arranged on the side of the model test box.

[0013] As a further technical solution, the front side wall is provided with an observation component for observing the interior of the model test box, and the observation component includes a transparent acrylic plate, and the transparent acrylic plate is fixed in a mounting frame, and the mounting frame is detachably connected to the bottom wall.

[0014] As a further technical solution, the loading frame includes columns and a base plate. The columns are arranged in two opposite groups, the base plate is connected between the two groups of columns, a connecting piece I is arranged between the upper parts of the columns, and a connecting piece II for support is arranged between the lower parts of the columns.

[0015] In a second aspect, the present invention further provides a test method for the operating tunnel surrounding rock-lining long-term interaction simulation test device as described above, comprising the following steps:

[0016] Assemble the model test box, fill the model test box, arrange monitoring elements, and pre-embed the tunnel lining structure;

[0017] After the filler reaches the set height, fix the front side wall to the bottom wall, assemble the test box, and adjust the upper pressure plate to the top of the filler;

[0018] After the overall laying of the model is completed, the overall maintenance stage of the model begins;

[0019] After the overall maintenance of the model is completed, a constant pressure loading test is carried out using a force-applying mechanism. After the test is completed, test data is obtained and analyzed to obtain the stress and deformation changes of the tunnel surrounding rock-lining structure under long-term loading conditions.

[0020] As a further technical solution, the size and position of the reserved aperture of the transparent acrylic plate on the front side wall are determined according to the shape of the tunnel section and the similarity ratio selected by the test, and the reserved hole is set in the transparent acrylic plate.

[0021] The beneficial effects of the present invention are as follows:

[0022] The test device of the present invention sets a fixed boundary on one side and arranges an elevator in the horizontal direction on the other side for loading, so as to realize the simulation of different lateral pressure coefficients, and also loads the vertical direction by the elevator to simulate the vertical ground stress; by setting the force-applying mechanism, it is possible to simulate different surrounding rock characteristics and ground stress characteristics, and realize the long-term stable pressure loading mode on the surrounding rock-lining structure, so as to study the timeliness law of the surrounding rock-lining interaction change, thereby more realistically reflecting the stress and deformation change of the tunnel surrounding rock-lining structure under the condition of long-term loading, thereby simulating the interaction process of the tunnel surrounding rock-lining structure under the influence of creep.

[0023] The test device of the present invention adopts a lift to increase pressure, and controls the lift to maintain constant pressure through a motor servo, so as to realize long-term service state simulation and long-term steady pressure loading on the surrounding rock-lining structure, and simulate the interaction process of the tunnel surrounding rock-lining structure under long-term influence.

[0024] The test device of the present invention has a mounting frame and a transparent acrylic plate fixed in the mounting frame on the front side wall. The mounting frame is detachably connected to the bottom wall of the model test box by bolts, which is convenient for assembly and disassembly, and is convenient for filling test materials and placing equipment. The transparent acrylic plate is provided with an aperture that is convenient for placing equipment in the tunnel, thereby improving the efficiency of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 It is a structural schematic diagram of the test device of the present invention;

[0027] Figure 2 A top view of the test device of the present invention;

[0028] Figure 3 It is a schematic diagram of the arrangement of the model test box and the loading frame of the present invention;

[0029] Figure 4 It is a structural schematic diagram of the force applying mechanism of the present invention;

[0030] In the figure: the distances or sizes between parts are exaggerated to show the positions of the parts, and the schematic diagram is for illustration only;

[0031] Among them, 1. screw; 2. upper lift; 3. crossbeam; 4. upper sensor; 5. upper pressure plate; 6. frame; 7. side pressure plate; 8. side sensor; 9. side lift; 10. screw; 11. acrylic plate; 12. bottom plate; 13. column; 14. motor; 15. motor. DETAILED DESCRIPTION

[0032] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0033] In a typical embodiment of the present invention, Figure 1 As shown, a long-term interaction simulation test device for surrounding rock and lining of an operating tunnel is proposed, including a model test box and a constant pressure loading device for simulating the pressure exerted by the soil layer, wherein the model test box includes a bottom wall, a right side wall, a rear side wall, a front side wall fixedly connected to the bottom wall in a detachable manner, and an observation component for observing the interior of the model test box, and the observation component is arranged on the front side wall; the constant pressure loading device includes a loading frame, a force applying mechanism and a force measuring mechanism, the model test box is located in the loading frame, and two groups of force applying mechanisms and force measuring mechanisms are respectively arranged on the upper part and the left part of the loading frame.

[0034] In this embodiment, the right side wall, rear side wall and side pressure plate 7 of the model test box form a three-sided structure with an open front side. The front side wall is detachably connected to the right side wall and the bottom wall by bolts to facilitate the filling of model materials into the model test box. The right side wall and the rear side wall are fixedly connected to each other. The side pressure plate 7 of the force-applying mechanism forms the left side wall of the model test box. The right side wall and the rear side wall of this embodiment are each fixedly connected to the bottom wall by bolts. The front side wall is a detachable part, which is easy to disassemble and assemble, and convenient for filling of test materials and placement of equipment.

[0035] In this embodiment, the bottom wall is composed of a whole piece of steel plate; the side pressure plate is composed of a whole piece of steel plate and is connected to the side force application mechanism; the rear side wall and the right side wall are both composed of a whole piece of steel plate, and an angle steel connector is welded at the connection between the rear side wall and the right side wall steel plates, and the angle steel connector is provided with connecting screw holes, and the two steel plates are fixedly spliced ​​to form two side walls. Since the bottom wall needs to withstand greater pressure, the thickness of the bottom steel plate is greater than the thickness of the rear side wall steel plate and the right side wall steel plate to improve the overall bearing strength; the outer side of the steel plate constituting the rear side wall has four sides and a diagonally crossed steel frame; the front side wall is composed of a four-sided and diagonally crossed steel frame and a transparent acrylic plate 11, and the steel frames are welded to each other, thereby improving the side wall's ability to restrain the model material during the test; the fixed rear side wall and right side wall are fixedly connected to the test box frame by bolts, and the front side wall steel plate is a detachable part.

[0036] The model test box is filled with fillers, and monitoring elements are arranged in the fillers. The monitoring elements arranged during the filling are mainly precision earth pressure boxes, which monitor the contact pressure between the lining and the soil and the internal pressure of the surrounding rock. In addition to the monitoring elements used here, resistance strain gauges are also arranged inside and outside the tunnel structure to test the strain values ​​inside and outside, so as to obtain the strains inside and outside and calculate the internal forces of the tunnel structure section; and displacement sensors are arranged on the inside of the tunnel to monitor the radial displacement of the tunnel.

[0037] In this embodiment, the transparent acrylic plate 11 of the front side wall forms an observation assembly, and the acrylic plate 11 is fixed in the mounting frame 6, and the mounting frame 6 is fixedly connected to the bottom wall of the model test box in a detachable manner by bolts, which is convenient for filling test materials, placing equipment, and observing the test. When in use, the size of the tunnel section in the model is obtained according to the similarity principle, and holes of the same size can be reserved at the corresponding position of the transparent acrylic plate, which is convenient for placing the test instrument and improving the test efficiency.

[0038] In this embodiment, the internal space size of the model test box is 1.25m×1.25m×0.3m, which is small in size and convenient for test personnel to carry.

[0039] The loading frame includes columns 13, a bottom plate 12, and connectors. Two groups of columns are provided. The left column is provided on the outside of the left side wall, and the right column is provided on the outside of the right side wall of the test box and is arranged in close contact with the right side wall. Each group of columns is one column with an I-shaped cross section. A connector I is fixedly connected between the upper parts of the columns on each side of the two groups of columns. The lower part of each group of columns is fixedly connected to the bottom plate 12 by bolts. A connector II for support is fixedly connected between the lower parts of the columns on each side of the two groups of columns. The model test box can be stably fixed on the bottom plate 12, fixed to the model test box, and ensure the stability of the model test box.

[0040] The connecting parts here are right-angled isosceles triangular steel plates. The two waists of the triangular steel plate of connecting part I are welded to the column and the beam respectively, and the two waists of the triangular steel plate of connecting part II are welded to the column and the bottom plate respectively. The connecting parts are small in size and are used to fix the test box.

[0041] In this embodiment, the bottom plate 12 is fixedly connected to the column 13 by bolts, and a plurality of bolt holes are provided at intervals along the lateral direction at both ends of the bottom plate 12 , so that the front side wall is stably fixed to the bottom plate 12 .

[0042] The lower ends of the two groups of columns 13 are fixed to the supporting steel plates fixed to the bottom plate 12 , so that the columns 13 are on the same plane to ensure the verticality and stability of the columns 13 .

[0043] Two groups of force-applying mechanisms are provided, including an upper force-applying mechanism and a side force-applying mechanism, wherein the upper force-applying mechanism includes a lead screw 1, an upper lift 2, a crossbeam 3, and an upper pressure plate 5 arranged in sequence from top to bottom, the upper lift 2 is welded and fixed above the crossbeam 3, the crossbeam 3 is fixed to the top of the column 13, the upper lift 2 is connected to the motor 14, the end of the lead screw 1 is connected to the upper pressure plate 5, the upper lift 2 is connected to the lead screw, driving the lead screw to move up and down, and then driving the upper pressure plate to move to fit the top of the model test box, and the upper pressure plate applies force to the top of the model test box. In the specific setting, the motor can use a servo motor, set the loading pressure on the external control unit according to the test plan, and use the servo motor to accurately control the lift to apply and maintain a constant pressure to the model test box through the upper pressure plate.

[0044] In this embodiment, the side force mechanism is arranged on the left side, but it can also be arranged on the right side according to the adjustment of the model test box; the side force mechanism includes a lead screw 10, a side lift 9, and a side pressure plate 7 arranged from left to right in sequence, the side lift 9 is welded and fixed to the left side of the left column, the side lift 9 is connected to the motor 15, the end of the lead screw 10 is connected to the side pressure plate 7, and the side lift 9 is connected to the lead screw, driving the lead screw to move left and right, and then driving the side pressure plate to move to fit the side of the model test box, and the side pressure plate applies force to the side of the model test box. In the specific setting, the motor can use a servo motor, set the loading pressure on the external control unit according to the test plan, and use the servo motor to accurately control the lift to apply and maintain a constant pressure to the model test box through the side pressure plate.

[0045] Since it is not easy to keep constant pressure when loading both sides of the model box in the horizontal direction at the same time, this embodiment sets a fixed boundary on the right side of the model box in the horizontal direction, and arranges a side elevator in the horizontal direction on the left side for loading, so as to achieve simulation of different lateral pressure coefficients, and also loads vertically through the elevator to simulate vertical ground stress. By setting a force-applying mechanism, different surrounding rock characteristics and ground stress characteristics can be simulated.

[0046] The force measuring mechanism includes a sensor and a control unit, wherein the upper sensor 4 is fixed between the end of the upper screw 1 and the top center of the upper pressure plate 5, and the side sensor 8 is fixed between the end of the left screw 10 and the left side center of the side pressure plate 7. The control unit is connected to the two sensors and is externally connected to this test device. According to the test plan, constant pressure can be maintained through motor servo control, and long-term service state simulation and long-term stable pressure loading can be realized on the surrounding rock-lining structure, simulating the interaction process of the tunnel surrounding rock-lining structure under long-term influence.

[0047] The device has the advantages of easy assembly and disassembly and quick operation, which is of great significance for the study of long-term service performance of tunnels during operation.

[0048] Based on the model test device described above, the present invention also proposes an operation method for a simulation test device for long-term interaction between surrounding rock and lining of an operating tunnel, which can simulate the long-term interaction between surrounding rock and lining structure of a tunnel; the steps are as follows:

[0049] A. When in use, determine the size and position of the reserved aperture of the transparent acrylic plate 11 on the front side wall for observing the interior of the model test box according to the tunnel cross-sectional shape and the similarity ratio selected for the test, so that the data line of the tunnel internal monitoring element must be led out from the reserved hole, and adjust the side pressure plate 7 to form a box with three sides closed with the rear side wall and the right side wall, and complete the preliminary assembly of the model test box;

[0050] B. After the model test box is assembled, fill the model test box. The fill needs to be laid in layers and compacted with a tamping hammer. During the filling process, the test monitoring elements must be arranged according to the test plan. After the filling reaches a certain height, the tunnel lining structure is pre-buried according to the test requirements. After the test monitoring elements in the tunnel are placed, the subsequent filling, arrangement of monitoring elements, etc. are carried out;

[0051] C. After the landfill material reaches the required height for the test, the front side wall is fixed to the bottom wall by bolts, the test box is assembled, and the upper pressing plate 5 is adjusted to the top position of the filler;

[0052] D. After the overall laying of the model is completed, enter the overall maintenance stage of the model, and allow the model room to be ventilated and maintained;

[0053] E. Finally, after the overall maintenance of the model is completed, the loading system is used to carry out a constant pressure loading test according to the established test plan. After the test is completed, the test data is obtained and analyzed to obtain the stress and deformation changes of the tunnel surrounding rock-lining structure under long-term loading conditions.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A long-term interaction simulation test device for surrounding rock and lining of an operating tunnel, characterized by: It includes a model test box and a constant pressure loading device, the constant pressure loading device includes a loading frame and a force applying mechanism, the model test box is located in the loading frame, the force applying mechanism includes an upper force applying mechanism and a side force applying mechanism, the upper force applying mechanism includes an upper lift, a first lead screw and an upper pressure plate, the upper lift is connected to the first lead screw to drive its vertical movement, and the end of the first lead screw is connected to the upper pressure plate; the side force applying mechanism includes a side lift, a second lead screw and a side pressure plate, the side lift is connected to the second lead screw to drive its horizontal movement, and the end of the second lead screw is connected to the side pressure plate; The force measuring mechanism includes an upper sensor, which is fixed between the end of the first lead screw and the upper pressing plate, and is connected to the control unit; The force measuring mechanism further includes a side sensor, which is fixed between the end of the second screw rod and the side pressure plate, and is connected to the control unit; The upper lift is connected to a motor, and the side lift is connected to a motor, wherein the motor is a servo motor; the servo motor controls the upper lift or the side lift to apply and maintain a constant pressure to the model test box through the upper pressure plate or the side pressure plate; The model test box body comprises a bottom wall, a right side wall, a rear side wall and a front side wall connected to form a box body, the front side wall is fixedly connected to the bottom wall in a detachable manner, an upper pressure plate is arranged on the top of the model test box body, and a side pressure plate is arranged on the side of the model test box body; the front side wall is provided with an observation component for observing the inside of the model test box body, the observation component comprises a transparent acrylic plate, the transparent acrylic plate is fixed in a mounting frame, the mounting frame is detachably connected to the bottom wall, and holes of the same size are reserved in the transparent acrylic plate; The outer side of the rear side wall is provided with steel frames on four sides and crossing diagonally; the front side wall is composed of steel frames on four sides and crossing diagonally and a transparent acrylic plate, and the steel frames are welded to each other.

2. The operating tunnel surrounding rock-lining long-term interaction simulation test device according to claim 1 is characterized in that: The upper elevator is fixed to the top of the loading frame.

3. The operating tunnel surrounding rock-lining long-term interaction simulation test device according to claim 1 is characterized in that: The side lifts are fixed to the sides of the loading frame.

4. The operating tunnel surrounding rock-lining long-term interaction simulation test device according to claim 1 is characterized in that: The loading frame comprises columns and a base plate. The columns are arranged in two opposite groups. The base plate is connected between the two groups of columns. Connecting members I are arranged between the upper parts of the columns, and connecting members II for support are arranged between the lower parts of the columns.

5. The test method of the operating tunnel surrounding rock-lining long-term interaction simulation test device according to any one of claims 1 to 4, characterized in that: The following steps are involved: Assemble the model test box, fill the model test box, arrange monitoring elements, and pre-embed the tunnel lining structure; After the filler reaches the set height, fix the front side wall to the bottom wall, assemble the test box, and adjust the upper pressure plate to the top of the filler; After the overall laying of the model is completed, the overall maintenance stage of the model begins; After the overall maintenance of the model is completed, a constant pressure loading test is carried out using a force-applying mechanism. After the test is completed, test data is obtained and analyzed to obtain the stress and deformation changes of the tunnel surrounding rock-lining structure under long-term loading conditions.

6. The test method according to claim 5, characterized in that: According to the shape of the tunnel section and the similarity ratio selected in the test, the size and position of the reserved aperture of the transparent acrylic plate on the front side wall are determined, and the reserved hole is set in the transparent acrylic plate.

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