Simulation test device for deterioration of supporting structure material and surrounding rock in underground water seepage environment

Abstract

The invention specifically discloses a support structure material and surrounding rock degradation simulation test device in an underground water seepage environment, and relates to the technical field of tunnel and underground engineering experiment equipment. The device is composed of a dynamic water pressure tank, a water flow control system and a water pressure adjusting system. The dynamic water pressure tank comprises a top plate and a bottom plate, the top plate is provided with the water pressure adjusting system composed of an air inlet valve, an air release valve and a pressure gauge, the bottom plate is provided with a water outlet, and the dynamic water pressure tank is internally provided with a seepage action bin and a clamping plate; the water flow control system is composed of a water tank, a constant flow water pump, a water inlet pipe, a flow control valve and a flow meter. The device can simulate the degradation process of a supporting structure material and a surrounding rock material under the combined action of different underground water seepage flow velocities and water pressures, can provide reliable test data for studying the durability and safety evaluation of an underground engineering structure through a simulation test, and has the characteristics of compact structure, simplicity and convenience in operation and strong controllability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel and underground engineering experiment equipment, in particular to a simulation test device for deterioration of supporting structure material and surrounding rock under groundwater seepage environment. BACKGROUND

[0002] With the increase in the number of tunnel projects, a large number of tunnels passing through water-rich areas have been built and put into operation. At present, composite supporting structure systems are widely used in tunnels, that is, the supporting structure includes surrounding rock + primary support + secondary lining. During the operation period of the tunnel, due to the presence of groundwater, under the combined action of water flow velocity and seepage water pressure, the tunnel supporting structure material is prone to deterioration phenomena such as corrosion and hidden corrosion, which may further cause many engineering problems, such as cracking and water leakage of the tunnel lining. In addition, for some weakly cemented surrounding rock, under the action of groundwater seepage, the deterioration phenomenon of fine particle migration and loss may occur. The deterioration of the tunnel supporting structure material directly affects the safety of underground engineering.

[0003] The existing test devices mainly study the influence of different groundwater environments on rock or concrete. For example, patent No. CN119959122A discloses a complex environment rock deterioration test device, which is composed of an integrated test cabin, a multifunctional component, a PLC controller and a multi-sensor detection module. This patent realizes the automation of integrated simulation of dry-wet cycle, freeze-thaw cycle, high-temperature baking and cold and humid environment, but does not involve groundwater seepage environment. Patent No. CN114383952A discloses a multi-field coupled rock mass deterioration simulation test system, which is composed of a test box, a stress simulation device, a heating plate, a scouring system, a surge machine and a displacement monitoring device. This patent realizes rock mass deterioration simulation and in-situ dry-wet cycle under multi-coupling action, but the device simulates the environment of bank slope rock, only applies surface scouring to the rock test piece, and cannot simulate the process of continuous loss of disintegrated fine particles caused by seepage penetrating the interior of the rock mass.

[0004] The existing technology has the following deficiencies: 1. The research on the deterioration of tunnel supporting structure material mainly focuses on carbonization environment, chloride salt environment and chemical corrosion environment. The research on the deterioration of surrounding rock mainly focuses on dry-wet cycle environment and freeze-thaw cycle environment, and the research on the deterioration law of supporting structure material and surrounding rock under groundwater seepage environment is insufficient.

[0005] 2. Most of the existing researches only consider the deterioration of rock or supporting material under the static action of groundwater, while relevant researches show that dynamic groundwater action also has a great influence on the deterioration of the material, which can greatly accelerate the deterioration process, especially for porous or fractured materials. However, few researches consider the influence of groundwater seepage, a dynamic factor, on the deterioration of supporting structure.

[0006] 3. The existing test device cannot effectively simulate the continuous loss process of disintegrated fine particles caused by seepage through the inside of the rock mass, and cannot simulate the slow precipitation-migration process of the hydration products of concrete materials, and it is difficult to truly reflect the long-term degradation law of the supporting structure materials and surrounding rock under the groundwater seepage environment.

[0007] Therefore, it is urgent to develop a test device capable of simulating the degradation process of supporting structure materials and surrounding rock under the groundwater seepage environment, so as to study the degradation law of supporting structure materials and surrounding rock under different seepage conditions, and provide a scientific basis for the design and maintenance of underground engineering supporting structure. SUMMARY

[0008] The purpose of the present application is to provide a degradation simulation test device for supporting structure materials and surrounding rock under the groundwater seepage environment, which solves the problem that the prior art cannot consider both water pressure and flow rate as dynamic factors, and cannot truly simulate the degradation process of supporting structure materials and surrounding rock caused by groundwater seepage, and provides reliable test data for related research.

[0009] To achieve the above-mentioned purpose, the present application provides a degradation simulation test device for supporting structure materials and surrounding rock under the groundwater seepage environment, comprising a dynamic water pressure tank, a water pressure adjusting system and a water flow control system. The upper part of the dynamic water pressure tank is provided with a top plate, the top plate is provided with a water inlet one, and the dynamic water pressure tank and the top plate are fixedly connected through bolts; the lower part of the dynamic water pressure tank is provided with a bottom plate and a metal base, and the dynamic water pressure tank is fixedly connected with the bottom plate and the metal base through bolts; four seepage action bins are arranged in the inside of the dynamic water pressure tank, and the seepage action bins are fixed by clamps. The water flow control system is composed of a water tank, a water tank control valve, a constant flow water pump, an inlet pipe and a water delivery pipe; the constant flow water pump is connected with the water tank through the water delivery pipe, one end of the inlet pipe is communicated with the water inlet one on the top plate, and the other end of the inlet pipe is connected with the constant flow water pump. The water pressure adjusting system is composed of an air inlet valve, an air outlet valve, a gas delivery pipe and a pressurizing air pump, the pressurizing air pump is connected with the air inlet valve through the gas delivery pipe, and the air inlet valve and the air outlet valve are arranged on the top plate.

[0010] Preferably, the seepage action bin comprises a bin shell and a top cover, the bin shell is screwed together with the inner thread of the top cover through the outer thread, and is equipped with a sealing ring to realize sealing, a water inlet two is opened on the top cover, a water outlet is arranged at the bottom of the seepage action bin, and the seepage action bin is made of transparent material.

[0011] Preferably, the water outlet at the bottom of the seepage action bin is connected with an outlet pipeline, a flow meter and a flow control valve are connected in series on the outlet pipeline, and a sampling barrel is arranged at the outlet of the outlet pipeline.

[0012] Preferably, a sample filter rack is placed inside the seepage effect bin, the sample filter rack is a conical platform with small top and large bottom, a grid hole is opened on the side wall of the conical platform and communicated with the inner cavity of the conical platform, and the inner cavity of the conical platform is communicated with the water outlet at the bottom of the seepage effect bin.

[0013] Preferably, the dynamic water pressure tank is made of transparent material.

[0014] Preferably, a roller is arranged below the metal base.

[0015] Preferably, the water pressure adjusting system further comprises a pressure gauge, and the pressure gauge is arranged on the top plate.

[0016] Preferably, the water tank control valve is arranged on the water conveying pipe.

[0017] Therefore, the application provides a simulation test device for deterioration of supporting structure material and surrounding rock under groundwater seepage environment, and has the following beneficial effects: (1) The water flow velocity and water pressure in the seepage effect bin can be simultaneously controlled by precisely regulating the water pressure adjusting system and the constant-flow water pump speed, so that the pressurized seepage environment of the tunnel supporting structure or the surrounding rock can be simulated, and the deterioration process of the rock or the supporting structure material under the combined action of water pressure and flow velocity, such as fine particle loss and migration of concrete hydration products, can be effectively restored, so that the blank of the prior art in which dynamic water pressure and flow velocity cannot be considered is filled.

[0018] (2) The dynamic water pressure tank and the seepage effect bin are made of transparent material, and multiple independent seepage effect bins are designed, which not only facilitates real-time observation of the macroscopic changes of the sample during the test, but also enables multiple control tests to be simultaneously carried out, thereby significantly improving the test efficiency and the reliability of the data. In addition, the conical platform structure and the grid hole design of the sample filter rack not only ensure that the water flow uniformly acts on the sample, but also filter the fine particles generated during the deterioration, thereby avoiding the blockage of the water outlet and further improving the stability and accuracy of the test.

[0019] (3) The application can reveal the deterioration mechanism of the supporting structure material and the surrounding rock under different pressure and flow velocity conditions in the groundwater seepage environment by combining micro-characteristic test and mechanical property test, and can determine the change rule of the mechanical parameters, so that the test data can provide scientific basis for durability evaluation and safety design of underground engineering structure, and has important engineering application value.

[0020] The technical solutions of the application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1This is a schematic diagram of the structure of a support structure material and surrounding rock degradation simulation test device under groundwater seepage environment according to the present invention; Figure 2 This is a schematic diagram of the seepage chamber in the simulation test device of the present invention; Figure 3 This is a schematic diagram of the clamping plate in the dynamic water pressure tank of this invention; Figure 4 This is a schematic diagram of the seepage direction in the seepage chamber of the present invention.

[0022] Figure Labels 100. Test specimen; 101. Dynamic water pressure tank; 102. Top plate; 103. Bottom plate; 104. Metal base; 105. Roller; 106. Seepage chamber; 106a. Top cover; 106b. Inlet 2; 106c. Specimen filter frame; 106d. Grille hole; 107. Clamping plate; 108. Fixing bolt; 109. Flow control valve; 110. Flow meter; 111. Sampling bucket; 201. Water tank; 202. Water supply pipe; 203. Water tank control valve; 204. Constant flow water pump; 205. Inlet pipe; 206. Inlet 1; 207. Outlet; 301. Pressurizing air pump; 302. Air supply pipe; 303. Air inlet valve; 304. Pressure gauge; 305. Air release valve. Detailed Implementation

[0023] To make the technical solutions, advantages, and objectives of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0024] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0025] Example like Figure 1 The diagram shown is a structural schematic of a test device for simulating the deterioration of support structure materials and surrounding rock under groundwater seepage conditions, which includes a dynamic water pressure box 101, a water pressure regulation system and a water flow control system. The upper portion of the hydrodynamic pressure box 101 is provided with a top plate 102, and the lower portion is provided with a bottom plate 103 and a metal base 104, the metal base 104 is installed with a roller 105, the hydrodynamic pressure box 101 and the top plate 102 are connected and fixed through a fixing bolt 108, and the hydrodynamic pressure box 101 is fixedly connected with the bottom plate 103 and the metal base 104 through the fixing bolt 108. The hydrodynamic pressure box 101 is internally provided with four seepage action bins 106, and the seepage action bin 106 is fixed in the hydrodynamic pressure box 101 by a clamping plate 107. The hydrodynamic pressure box 101 is made of transparent material, which is convenient for observing the change of the sample in the test process.

[0026] As shown in Figures 2-3 , the seepage action bin 106 includes a bin shell and a top cover 106a, the bin shell is screwed together with the inner thread of the top cover 106a through the outer thread, and a sealing ring is arranged at the connection to realize sealing. A water inlet two 106b is opened on the top cover; the seepage action bin 106 is also made of transparent material, which is convenient for observing the change process of the sample under the action of water flow. The bottom of each seepage action bin 106 is connected with a water outlet 207 and is arranged at equal intervals from left to right, and each water outlet 207 is provided with a water outlet pipeline, each water outlet pipeline is connected with a flow meter 110 and a flow control valve 109, and a sampling bucket 111 is arranged at the outlet of each water outlet pipeline. By adjusting the flow control valve 109, the water flow from each water outlet can be accurately controlled to simulate different underground water seepage conditions. The seepage action bin 106 is placed with a sample filter screen frame 106c, the sample filter screen frame 106c is a conical frustum shape with a small upper portion and a large lower portion, a grid hole 106d is opened on the side wall of the conical frustum and communicates with the inner cavity of the conical frustum, and the inner cavity of the conical frustum communicates with the water outlet 207 at the bottom of the seepage action bin 106. This design makes the water flow uniformly through the sample, prevents the sample from blocking the water outlet, and ensures the continuity and stability of the water flow. The design of the conical frustum shape increases the contact area of the water flow and the sample, and improves the simulation effect.

[0027] As shown in Figure 4 , in the seepage action bin 106, the seepage action direction is from the upper water inlet two 106b to the lower sample filter screen frame 106c, when the rock disintegrates to produce cracks, a new seepage channel is formed, the water flow will flow to the lower sample filter screen frame 106c through the inside of the rock mass, and the fine rock particles will be filtered by the grid hole 106d during the flow process.

[0028] The water flow control system is composed of a water tank 201, a water delivery pipe 202, a water tank control valve 203, a constant flow water pump 204 and a water inlet pipe 205. The constant flow water pump 204 is connected with the water tank 201 through the water delivery pipe 202, and the constant flow water pump 204 draws water in the water tank 201 into the water inlet pipe 205, which is in communication with a water inlet 206 on the top plate 102 of the upper portion of the dynamic water pressure tank 101. The constant flow water pump 204 can provide stable water flow, and the water tank control valve 203 is arranged on the water delivery pipe 202 to control the total amount of water flow and ensure the stability and controllability of water flow during the test.

[0029] The water pressure adjusting system is composed of a pressurized air pump 301, a gas delivery pipe 302, an air inlet valve 303, a pressure gauge 304 and an air outlet valve 305. The pressurized air pump 301 is connected with the air inlet valve 303 through the gas delivery pipe 302, and the air inlet valve 303, the pressure gauge 304 and the air outlet valve 305 are arranged on the top plate 102. By controlling the on-off of the pressurized air pump 301 and the air inlet valve 303 and the air outlet valve 305, the air pressure in the dynamic water pressure tank 101 can be adjusted, so as to change the water pressure acting on the sample and simulate the pressure conditions of groundwater at different depths.

[0030] During the test, first, the supporting structure material or surrounding rock sample to be tested is placed on the sample filter screen frame 106c, and then the sample filter screen frame 106c is placed in the seepage action bin 106, and the top cover 106a is tightened.

[0031] The air inlet valve 303 is closed, the flow control valve 109 is closed, the water tank control valve 203 and the constant flow water pump 204 are opened, the water in the water tank 201 is drawn into the dynamic water pressure tank 101, the air outlet valve 305 is opened during water injection, the air in the dynamic water pressure tank 101 is discharged, when the water reaches 1 / 2 of the volume of the dynamic water pressure tank 101 and submerges the test sample 100, the water tank control valve 203 is closed, and the air outlet valve 305 is closed.

[0032] The rotation speed of the constant flow water pump 204 is adjusted to control the water flow to reach the required flow rate of the test, the flow control valve 109 is slowly rotated, the reading of the flow meter 110 is observed, and when the reading is consistent with the set flow rate of the constant flow water pump 204, the rotation is stopped, at this time, a stable flow rate is formed in the dynamic water pressure tank 101. During the test, the constant flow water pump 204 continuously works to make the water in a flowing state, so as to simulate the seepage state of groundwater.

[0033] The pressurized air pump 301 is connected with the air inlet valve 303 through the air conveying pipe 302, the pressurized air pump 301 is opened, the air inlet valve 303 is slowly rotated, the reading of the pressure gauge 304 is observed, when the pressure displayed on the pressure gauge 304 reaches the required pressure of the test, the air inlet valve 303 and the pressurized air pump 301 are closed, and the precise adjustment is carried out through the air outlet valve 305, at this time, the external air pressure is transmitted to the water through the pressurized air pump 301, and the simulation of the underground water pressure is realized. During the test, the reading of the pressure gauge 304 is observed every certain period of time, when the pressure is lower than the required pressure of the test, the above steps are repeated for adjustment again.

[0034] During the test, the water in the water tank 201 is supplemented every certain period of time, the residue generated by the deterioration of the test sample 100 on the sample filter frame 106c is cleaned every certain period of time, the solution in the sampling barrel 111 is collected every certain period of time for subsequent chemical composition analysis, and the deterioration process is photographed by the camera every certain period of time.

[0035] After the test is completed, the air inlet valve 303 is closed, the air outlet valve 305 is opened, the pressure in the dynamic water pressure tank 101 is released, and the release is completed when the reading of the pressure gauge 304 is zero; the fixing bolt 108 of the top plate 102 is unscrewed, the top plate 102 is removed, the reacted test sample 100 is taken out, and the solid phase composition, solid phase appearance characteristics, pore structure and mechanical properties of the supporting structure sample before and after the deterioration are analyzed by using the microscopic characteristic test such as the X-ray diffractometer, the pore size distribution instrument and the electron microscope and the mechanical test system such as the triaxial compression and the uniaxial compression, so that the deterioration mechanism of the supporting structure material and the surrounding rock under different pressure conditions and flow velocity conditions in the underground water seepage environment is revealed.

[0036] It is worth noting that the contents not elaborated in the present application are all prior art and are well known to those skilled in the art.

[0037] Therefore, the present application provides a supporting structure material and surrounding rock deterioration simulation test device under the underground water seepage environment, the water flow velocity and the water pressure size in the seepage action bin body can be accurately controlled by adjusting the water pressure adjusting system and the constant-flow water pump rotating speed, so that the pressurized seepage environment in which the tunnel supporting structure or the surrounding rock is located can be truly simulated, the deterioration process of the fine particle loss and the migration of the concrete hydration product under the combined action of the water pressure and the flow velocity can be effectively restored, compared with the prior art, the device can consider the influence of the two dynamic factors of the water pressure and the flow velocity on the deterioration of the supporting structure material at the same time, the mechanical test and the microscopic characteristic test are combined, the deterioration mechanism and the mechanical parameter change rule of the supporting structure under the underground water seepage condition can be further determined, and reliable test data can be provided for the durability and safety research of the underground engineering.

[0038] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A test device for simulating the deterioration of support structure materials and surrounding rock under groundwater seepage conditions, characterized in that, This includes a dynamic water pressure tank, a water pressure regulation system, and a water flow control system; The dynamic water pressure box is provided with a top plate at the top, and a water inlet is provided on the top plate. The dynamic water pressure box and the top plate are fixedly connected by bolts. The dynamic water pressure box is provided with a bottom plate and a metal base at the bottom, and the dynamic water pressure box is fixedly connected to the bottom plate and the metal base by bolts. The dynamic water pressure box is provided with four seepage chambers inside, and the seepage chambers are fixed by clamps. The water flow control system consists of a water tank, a water tank control valve, a constant flow water pump, an inlet pipe, and a delivery pipe; the constant flow water pump is connected to the water tank through the delivery pipe, one end of the inlet pipe is connected to the water inlet on the top plate, and the other end of the inlet pipe is connected to the constant flow water pump. The water pressure regulating system consists of an air inlet valve, an air outlet valve, an air supply pipe, and a pressurizing air pump. The pressurizing air pump is connected to the air inlet valve through the air supply pipe. The air inlet valve and the air outlet valve are located on the top plate.

2. The experimental device for simulating the deterioration of support structure materials and surrounding rock under groundwater seepage environment according to claim 1, characterized in that, The seepage chamber includes a chamber shell and a top cover. The chamber shell is screwed together with the top cover by an external thread and is equipped with a sealing ring to achieve a seal. A second water inlet is opened on the top cover, and a water outlet is opened at the bottom of the seepage chamber. The seepage chamber is made of transparent material.

3. The experimental device for simulating the deterioration of support structure materials and surrounding rock under groundwater seepage environment according to claim 2, characterized in that, The outlet at the bottom of the seepage chamber is connected to a water outlet pipe, which is connected in series with a flow meter and a flow control valve. A sampling bucket is provided at the outlet of the water outlet pipe.

4. The test device for simulating the deterioration of support structure materials and surrounding rock under groundwater seepage environment according to claim 3, characterized in that, The seepage chamber contains a sample filter frame, which is a truncated cone that is smaller at the top and larger at the bottom. A grid hole communicating with the inner cavity of the truncated cone is opened on the side wall of the truncated cone. The inner cavity of the truncated cone is connected to the water outlet at the bottom of the seepage chamber.

5. The experimental device for simulating the deterioration of support structure materials and surrounding rock under groundwater seepage environment according to claim 1, characterized in that, The dynamic water pressure box is made of transparent material.

6. The experimental device for simulating the deterioration of support structure materials and surrounding rock under groundwater seepage environment according to claim 1, characterized in that, The metal base is equipped with rollers.

7. The experimental device for simulating the deterioration of support structure materials and surrounding rock under groundwater seepage environment according to claim 1, characterized in that, The water pressure regulating system also includes a pressure gauge, which is installed on the top plate.

8. The test device for simulating the deterioration of support structure materials and surrounding rock under groundwater seepage environment according to claim 1, characterized in that, The water tank control valve is located on the water supply pipe.

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