Test equipment and method for simulating stratum deformation caused by confined water exploitation and recharge

Abstract

The invention relates to the technical field of environmental geological engineering, in particular to test equipment and method for simulating stratum deformation caused by confined water exploitation and recharge, and the test equipment comprises a model box frame, a cross elevator, a water suction pump, a sedimentation tank and a model box, and is characterized in that the inner wall of the model box frame is fixedly connected with organic tempered glass; a counter-force beam is fixedly connected to the top of the model box frame, three mechanical jacks are fixedly installed on the top of the inner side of the counter-force beam, a plurality of internal water injection pipes which are distributed at equal intervals are laid on the inner side of the model box frame, and a steel wire hose is connected between every two adjacent internal water injection pipes in a threaded mode. Through cooperation of the structures, the large-scale physical model test device which is rich in function, reasonable in design, practical and feasible is formed, and the process of ground subsidence and springback caused by dynamic changes of multi-layer pressure-bearing water levels can be simulated.

Description

Technical Field

[0001] The invention relates to the technical field of environmental geological engineering, in particular to test equipment and a method for simulating stratum deformation caused by pressurized water exploitation and reinjection. Background Art

[0002] Land subsidence, also known as ground subsidence or ground sinking, is a slow-changing geological disaster caused by the synergistic effects of regional geological forces and human engineering activities. The shallow soil near the surface (usually within a depth of 400m) undergoes elastic-plastic compression deformation, causing the local or overall surface elevation of the region to show negative growth. Its complex cause mechanism, wide impact range, slow disaster-pregnancy process, large disaster losses, and close relationship with human resource exploitation and utilization engineering activities are the typical characteristics of land subsidence compared with other geological disasters.

[0003] The causes of ground subsidence are relatively complex and are usually analyzed from the perspective of natural factors and human factors. Natural factors mainly refer to regional geological forces. From this perspective, the causes of ground subsidence are: (1) the loose and semi-loose rock and soil layers near the surface gradually consolidate under the action of the gravity field to form hard or semi-hard strata. In the process, the surface subsides due to the reduction of the thickness of the underlying strata; (2) due to the strong tensile stress induced by tectonic movement, the fault blocks collapse, resulting in ground depression and subsidence: such as the formation of grabens, fault basins, and large rift valleys; (3) seismic activity induces ground subsidence. At present, with the continuous exploitation and utilization of resources by humans and the implementation of various large-scale engineering construction activities, human factors have become the primary inducing factor of ground subsidence. Man-made ground subsidence is widely seen in underground resource exploitation areas such as groundwater, natural gas, oil, and solid minerals. Among them, the uncontrolled exploitation of groundwater causes the groundwater level to drop sharply, causing the effective stress of the aquifer soil to increase, and the soil skeleton is compressed, which can then cause ground subsidence and become the main cause of urban ground subsidence. In recent years, as local governments at all levels have paid more attention to urban land subsidence prevention and control and taken effective prevention and control measures, groundwater levels in many places have rebounded to varying degrees, accompanied by ground rebound. At present, there are relatively few studies on the cause mechanism of ground rebound.

[0004] Physical model tests have always been an extremely important research method in the field of ground subsidence geological disasters. They can not only be used to verify the results of different theoretical analyses and numerical simulation calculations, but also directly guide the design and construction of actual projects based on model tests. Physical model tests can simulate complex geological structures more realistically and comprehensively, and can intuitively and vividly simulate the entire process of stress, deformation and destruction of strata, revealing the influence of various human-controllable factors on the gestation and evolution of geological disasters, thereby establishing a connection between the basic mechanical behavior research of rock and soil in the laboratory and the actual disaster prevention and control projects, providing a basis for the establishment of new theories and mathematical models, and then providing technical support for monitoring, prevention, control and governance of geological disasters.

[0005] At present, both at home and abroad, there have been in-depth studies on ground subsidence caused by groundwater level decline, but there are few studies on the mechanism of ground rebound caused by groundwater rise. There is still a lack of a mature physical model test system specifically used to study the whole process of ground subsidence and rebound mechanism, especially model tests for the formation mechanism and evolution mechanism of ground subsidence and rebound under water-soil coupling conditions. Some domestic scholars have conducted some physical model test studies on ground subsidence, but due to the limitations of test sites, system platforms and monitoring equipment, many studies have only focused on a single disaster factor such as upper load, soil type, groundwater level, rainfall intensity, etc., and have never conducted physical model test studies on ground subsidence caused by the coupling effect of internal soil fracture dislocation and dynamic changes in groundwater level. In addition, although some scholars have conducted physical model tests on the mechanism of ground subsidence caused by groundwater level decline, physical model tests on the response mechanism of aquifers and impermeable layers under different water level change modes have not been carried out. Moreover, the test platform used for groundwater level decline is usually a relatively simple model box, which can only simulate one aquifer and cannot study factors such as water level changes of aquifers at different burial depths. To this end, we propose an experimental device and method for simulating formation deformation caused by multi-layer confined water extraction and reinjection. Summary of the invention

[0006] The purpose of the present invention is to provide a test device and method for simulating stratum deformation caused by pressurized water extraction and reinjection, which is a large-scale physical model test device with rich functions, reasonable design, and practical feasibility, and can simulate the process of ground subsidence and rebound caused by dynamic changes of multi-layer pressurized water levels.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a test device for simulating stratum deformation caused by pressurized water exploitation and reinjection, comprising a model box frame, a cross lift, a water pump, a sedimentation tank and a model box, characterized in that: the inner wall of the model box frame is fixedly connected to organic tempered glass, the top of the model box frame is fixedly connected to a reaction beam, three mechanical jacks are fixedly installed on the top of the inner side of the reaction beam, the inner side of the model box frame is laid with internal water injection pipes distributed equidistantly and in multiple numbers, a steel wire hose is threadedly connected between two adjacent internal water injection pipes, and the internal water injection pipes close to the left and right sides of the inner cavity of the model box frame are connected to the ends thereof. A rigid PVC pipe, a water hole is provided on the surface of the water pipe of the internal water injection pipe, a water filter is arranged on the outside of the water hole, a water tank is fixedly installed on the top of the cross lift, the top of the water pump is connected with the sedimentation tank and the water tank respectively through pipes, and the connected pipes are respectively provided with a first valve, a rigid water extraction and injection pipe is connected between one end of the water pump and the rigid PVC pipe, a second valve is arranged on the rigid water extraction and injection pipe near one end of the rigid PVC pipe, water outlets are arranged on the left and right sides of the model box frame, and ordinary pressure measuring tubes and U-shaped pressure measuring tubes connected with different aquifers are respectively threadedly connected near the water outlets on the left and right sides of the model box frame.

[0008] Preferably, the internal water injection pipe is made of rigid PVC as a whole, and two adjacent internal water injection pipes can be disconnected or connected by a steel hose thread.

[0009] Preferably, the cross elevator includes an elevator base, an elevator slide rail, a pulley, an elevator cross bracket, a cross bracket connecting rod, and an elevator top plate platform. The elevator slide rail is fixedly installed at the front and rear ends of the top of the elevator base, the pulley is fixedly installed at the left and right ends of the inner side of the elevator slide rail, the elevator cross bracket is fixedly installed at the upper end of the pulley, the cross bracket connecting rod is movably connected to the inner side of the elevator cross bracket, and the elevator top plate platform is fixedly installed at the upper end of the elevator cross bracket.

[0010] Preferably, an auxiliary ladder is fixedly installed on the left end of the front side of the model box frame.

[0011] Preferably, a pressure measuring tube fixing rod fixedly connected to a common pressure measuring tube is fixedly installed on the left side of the model box frame.

[0012] A test method for simulating formation deformation caused by pressurized water production and reinjection, the method comprising the following steps:

[0013] S1: Test preparation stage, the model box of the experimental equipment includes a base, a model box frame, organic tempered glass, an internal water injection pipe, multiple rigid water extraction and injection pipes, a water pump, a U-shaped pressure measuring tube, a common pressure measuring tube, a reaction beam, a mechanical jack, two sedimentation tanks, two water storage tanks, a cross lift and experimental data monitoring equipment, wherein the model box is directly placed on the ground, or a base can be separately set and placed at the bottom of the model box frame to make the model box off the ground, and the organic tempered glass is set on the model box frame, and a layer of structural glue is applied on the inner and outer surfaces of the contact surface between the two to ensure the overall sealing of the model box, and then the test soil material is laid inside the model box;

[0014] S2: When laying the test soil material into the model box through the space on both sides of the reaction beam at the top of the model box, first screen out the large particles larger than the diameter of the water hole, and lay a thin layer on the upper and lower sides of the internal water injection pipe to act as a filter, and together with the water filter on the outside of the water pipe, block the fine particles in the soil material from entering the internal water injection pipe, ensuring the smooth progress of the simulated ground settlement rebound test caused by the extraction of the confined aquifer and the recharge of groundwater;

[0015] S3: When laying the test soil material, a detachable internal water injection pipe is set up and laid at different heights to simulate multiple confined water aquifers at different levels, and each internal water injection pipe can be connected to a pump through a rigid pumping pipe, which can simulate the actual situation of extracting confined water at different depths;

[0016] S4: After the test soil material and monitoring instruments inside the model box are laid, a pressure plate of the size required for the test is added to the upper surface of the model box, and the upper surface of the pressure plate is connected to the top of the mechanical jack. At this time, the tops of the three mechanical jacks arranged on the reaction beam frame are simultaneously extended under the action of the pressure plates of the same size on the upper surface of the model box, and quantitative pressure is applied to the test soil material inside the model box to simulate the influence of the ground building load on the stratum deformation;

[0017] S5: Simulation stage, in the process of simulating the injection of pressurized water, the first valve on the pipe connecting the water storage tank and the water pump and the second valve on the pipe connecting the water pumping pipe and the rigid PVC pipe can be opened, and the first valve set on the pipe connecting the sedimentation tank and the water pump can be closed. The water storage tank can provide a certain water pressure and water flow to the inside of the internal water injection pipe, so that the water flow can quickly fill the water pipe between the rigid PVC pipe and the internal water injection pipe, and evenly inject water into the test soil material laid inside the model box through the water hole to form a pressurized aquifer;

[0018] S6: In the process of simulating ground subsidence induced by extraction of confined water, the first valve on the pipe connecting the water storage tank and the pump and the second valve corresponding to the non-simulated pumped confined water aquifer can be closed, and the first valve set on the pipe connecting the sedimentation tank and the pump and the second valve corresponding to the corresponding pumped confined water aquifer can be opened to discharge the simulated extracted confined water into the sedimentation tank, so that the amount of water extracted can be easily observed, and the fine sediment extracted with the water flow will also settle to the bottom of the sedimentation tank for later water recycling;

[0019] S7: In the process of simulating the ground rebound induced by the injection of confined water, the first valve on the pipe connecting the water storage tank and the water pump and the second valve corresponding to the corresponding water-injected confined water aquifer can be opened, and the first valve set on the pipe connecting the sedimentation tank and the water pump and the second valve corresponding to the non-simulated water-injected confined water aquifer can be closed. The water storage tank can inject water into the internal water injection pipe, so that the water flow can quickly fill the rigid PVC pipe and the water pipe of the internal water injection pipe, and evenly inject water into the test soil material through the water hole to ensure the stable recovery of the water level of the confined water aquifer;

[0020] S8: During the monitoring phase, the experimental data monitoring equipment is used to monitor the changes in the test soil material in the model box, and analyze the dynamic changes in ground settlement or rebound and pressure water level based on the change data of the test soil material.

[0021] Preferably, in step S1, the test soil material refers to the soil material of the simulated stratum set for each working condition of the experimental setting, and the test personnel can adjust its composition and proportion according to actual needs.

[0022] Preferably, the experimental data monitoring equipment in step S1 includes a soil pressure sensor, a moisture content meter, a pore water pressure sensor, an optical fiber strain monitoring, a layered marker settlement meter, a laser displacement meter and a camera. The monitoring devices of the soil pressure sensor, the moisture content meter, the pore water pressure sensor, the optical fiber strain monitoring and the layered marker settlement meter are buried inside the test soil material, the laser displacement meter is arranged on the upper surface of the test soil material, and the camera is arranged outside the model box 14.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The test equipment can simulate different stratum structures and different positions of confined aquifers by opening holes at different vertical positions on the side wall of the box and connecting rigid pumping and injection pipes, so as to simulate the ground subsidence caused by single-layer or multi-layer confined water exploitation and the ground rebound caused by reinjection. It has the advantages of rich functions and strong applicability.

[0025] 2. The internal water injection pipe of the test equipment is opened with holes at a certain interval around it. According to the Bernoulli principle, the aperture of the water outlet hole near the water injection port should be designed to be larger, and the aperture of the water outlet hole far from the water injection port should be designed to be smaller, so as to ensure that the water pressure of each water outlet hole of the internal water injection pipe is basically the same, so that water can be evenly injected into various positions of the aquifer to maintain the pressure bearing capacity of the aquifer. The internal water injection pipe is connected by PVC pipe fittings and joints. The pipe body has a small diameter, light weight, and less disturbance to the soil layer. At the same time, the internal water injection pipe of each layer is composed of multiple components spliced ​​together and connected in the middle with a hose, which is easy to assemble and can be combined according to actual needs. Compared with the overall structure, this design uses flexible connections to reserve a certain allowable settlement reserve between each component, which can avoid the damage of the internal water injection pipe caused by uneven settlement of the aquifer.

[0026] 3. The test equipment can control the water pressure, water flow speed or flow rate by adjusting the height of the water tank or the water pump, and can simultaneously inject water into different aquifers or inject water into a specified aquifer by opening or closing different valves.

[0027] 4. The pumping device utilizes the pipe system of the water injection device and is connected to a pump controlled by a variable frequency drive servo, so that the water in the aquifer can be evenly pumped out according to a certain flow rate or depth. At the same time, since the injection and pumping pipes of each aquifer are independent of each other, different valves can be opened or closed to ensure that only groundwater from a specific aquifer is extracted. At the same time, a backfiltration device and a sedimentation tank are set up, and the water in the box can be recycled.

[0028] 5. A loading device is designed to compact the laid soft soil to the required density before water injection and consolidation, so that its compression modulus is close to the theoretical conversion value, avoiding the influence of consolidation settlement on the test, and restoring the physical and mechanical properties of the soil in the real stratum as much as possible, so that the physical model test phenomenon is closer to reality, thus providing guidance for actual engineering. At the same time, the loading device can also be used to simulate the influence of ground building loads on ground settlement, as well as the coupling effect of building load loading and groundwater level drop and ground settlement. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the test equipment of the present invention;

[0030] Figure 2 For the present invention Figure 1 Another perspective structural diagram of;

[0031] Figure 3 A schematic diagram of the internal water injection pipe structure designed for simulating the extraction of pressurized water in the present invention;

[0032] Figure 4 It is a partial schematic diagram of the internal water injection pipe of the present invention;

[0033] Figure 5 It is a schematic diagram of the structure of the cross lifter of the present invention;

[0034] Figure 6 It is a schematic diagram of the reaction beam and mechanical jack structure of the present invention.

[0035] In the figure: 1. model box frame; 2. organic tempered glass; 3. reaction beam; 4. internal water injection pipe; 41. steel wire hose; 42. rigid PVC pipe; 43. water hole; 44. water filter; 5. mechanical jack; 6. auxiliary ladder; 7. U-shaped pressure measuring tube; 70. ordinary pressure measuring tube; 8. sedimentation tank; 9. water pump; 10. first valve; 11. water storage tank; 12. cross lift; 121. lift base; 122. lift slide rail; 123. pulley; 124. lift cross bracket; 125. cross bracket connecting rod; 126. lift top plate platform; 13. rigid water injection and extraction pipe; 14. model box; 15. water outlet; 16. pressure measuring tube fixing rod; 17. second valve. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "terminal", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0038] See also Figure 1-Figure 6As shown, the present invention provides a technical solution: a test device for simulating stratum deformation caused by pressurized water exploitation and reinjection, comprising a model box frame 1, a cross lift 12, a water pump 9, a sedimentation tank 8 and a model box 14, characterized in that: an organic tempered glass 2 is fixedly connected to the inner wall of the model box frame 1, a reaction beam 3 is fixedly connected to the top of the model box frame 1, three mechanical jacks 5 are fixedly installed on the top of the inner side of the reaction beam 3, a plurality of internal water injection pipes 4 are equidistantly distributed and arranged on the inner side of the model box frame 1, a steel wire hose 41 is threadedly connected between two adjacent internal water injection pipes 4, the internal water injection pipes 4 close to the left and right sides of the inner cavity of the model box frame 1 are connected to the terminals with rigid PVC pipes 42, a water hole 43 is provided on the water pipe surface of the internal water injection pipe 4, and a water filter is provided on the outer side of the water hole 43 Net 44, a water tank 11 is fixedly installed on the top of the cross lift 12, the top of the water pump 9 is connected with the sedimentation tank 8 and the water tank 11 respectively through pipes, and the connected pipes are respectively provided with a first valve 10, and water can be pumped and injected from the left and right sides of the model box 14 through a rigid pumping and injection pipe 13 and a rigid PVC pipe 42, and the water flow switch is controlled by the connected first valve 10 and the second valve 17, a rigid pumping and injection pipe 13 is connected between one end of the water pump 9 and the rigid PVC pipe 42, and a second valve 17 is provided on the rigid pumping and injection pipe 13 near one end of the rigid PVC pipe 42, and a water outlet 15 is provided on the left and right sides of the model box frame 1, and ordinary pressure measuring pipes 70 and U-shaped pressure measuring pipes 7 connected to different aquifers are respectively threadedly connected near the water outlets 15 on the left and right sides of the model box frame 1.

[0039] Specifically, the internal water injection pipe 4 is made of rigid PVC, and two adjacent internal water injection pipes 4 can be disconnected or threadedly connected through a steel hose 41 .

[0040] Specifically, the cross lift 12 includes a lift base 121, a lift rail 122, a pulley 123, a lift cross bracket 124, a cross bracket connecting rod 125, and a lift top plate platform 126. The lift rail 122 is fixedly mounted on the front and rear ends of the top of the lift base 121, the pulley 123 is fixedly mounted on the left and right ends of the inner side of the lift rail 122, the lift cross bracket 124 is fixedly mounted on the upper end of the pulley 123, and the cross bracket connecting rod 125 is movably connected to the lift cross bracket. On the inner side of the frame 124, the elevator top plate platform 126 is fixedly installed on the upper end of the elevator cross bracket 124, and the upper part of the cross elevator 12 is provided with an elevator top plate platform 126 for placing the water tank 11 and fixing it thereto, and the bottom of the cross elevator 12 is provided with an elevator slide rail 122 fixed on the elevator base 121, and the elevator slide rail 122 is connected to the elevator cross bracket 124 through a pulley 123, and the height of the water tank 11 can be controlled by controlling the position of the pulley 123 on the elevator slide rail 122.

[0041] Specifically, an auxiliary ladder 6 is fixedly installed on the left end of the front side of the model box frame 1, and the top of the auxiliary ladder 6 is welded to the model box frame 1. Considering that the overall size of the model box 14 is relatively large, after an auxiliary ladder 6 is installed on the outside, it is convenient for the test personnel to enter the model box 14 to carry out preparatory work such as laying the test soil and deploying the monitoring equipment in the early stage of the test, as well as to observe the top of the model box 14 after the experiment starts.

[0042] Specifically, a pressure measuring tube fixing rod 16 fixedly connected to a common pressure measuring tube 70 is fixedly installed on the left side of the model box frame 1 .

[0043] The test method for simulating formation deformation caused by confined water extraction and reinjection comprises the following steps:

[0044] S1: Test preparation stage, the model box 14 of the experimental equipment includes a base, a model box frame 1, organic tempered glass 2, an internal water injection pipe 4, multiple rigid water extraction and injection pipes 13, a water pump 9, a U-shaped pressure measuring tube 7, a common pressure measuring tube 70, a reaction beam 3, a mechanical jack 5, two sedimentation tanks 8, two water storage tanks 11, a cross lift 12 and experimental data monitoring equipment, wherein the model box 14 is directly placed on the ground, or a base can be separately set and placed at the bottom of the model box frame 1 to make the model box 14 leave the ground, and the organic tempered glass 2 is set on the model box frame 1, and a layer of structural glue is applied on the inner and outer surfaces of the contact surface between the two to ensure the overall sealing of the model box 14, and then, the test soil material is laid inside the model box 14;

[0045] S2: When laying the test soil material inside the model box 14, first screen out large particles larger than the diameter of the water filter 44, and lay a thin layer on the upper and lower sides of the internal water injection pipe 4 to play a filtering role. Together with the water filter 44, it blocks the fine particles in the soil material from entering the internal water injection pipe 4, ensuring the smoothness of the simulated ground settlement rebound test caused by the extraction of pressurized aquifers and groundwater recharge.

[0046] S3: When laying the test soil material, a detachable internal water injection pipe 4 is provided, which is laid at different heights to simulate multiple confined water aquifers at different levels, and each internal water injection pipe 4 can be connected to a pump 9 through a rigid pumping and injection pipe 13, so as to simulate the actual situation of extracting confined water at different depths, such as Figure 4The water holes 43 in the model box 14 are divided into vertical holes and transverse holes. The two types of water holes 43 are evenly distributed on the rigid PVC pipe 42. Both ends of the internal water injection pipe 4 are provided with water inlets, which are respectively connected to the water storage tanks 11 on both sides through the rigid pumping and injection pipes 13. The water in the water storage tank 11 can provide a certain water pressure and water flow to the inside of the internal water injection pipe 4, so that the water flow can quickly fill the rigid PVC pipe 42 and the water pipes of the internal water injection pipe 4. Water is evenly injected into the test soil material laid inside the model box 14 through the water holes 43 to form a pressurized aquifer. Considering that the overall size of the model box 14 is relatively large, it may not be sufficient to inject water into the test soil by relying on the water pressure provided by the water storage tanks 11 on both sides. When the water head inside the model box 14 rises to a certain height, the height of the water storage tank 11 provides The water pressure makes it difficult to inject water into the model box 14. At this time, a water pump 9 can be added between the internal water injection pipe 4 and the water storage tank 11, and connected through the rigid water pumping and injection pipe 13. The water pressure provided by the water pump 9 can help the water storage tank 11 to inject water into the test soil material inside the model box 14 to ensure the pressure-bearing capacity of the pressurized aquifer. The rigid water pumping and injection pipe 13 at the outlet of each layer of the internal water injection pipe 4 is provided with a second valve 17 to control the water flow of different pressurized water aquifers. A water filter 44 is provided on the outside of the water pipe of the internal water injection pipe 4. The water filter 44 can filter out large particles in the sand layer to prevent soil particles from entering the pipe and clogging the pipe, so that water can freely enter and exit the rigid PVC pipe 42 to ensure smooth water flow; according to the overall size of the model box 14, the internal water injection pipe 4 is designed as follows Figure 3 The three (or more) independent water injection pipes 4-1, 4-2, and 4-3 shown are connected by a steel hose 41 with a rotating thread, and can be freely disassembled and assembled. The length of the steel hose 41 connected between two adjacent independent water injection pipes is greater than the straight-line distance between the two independent water injection pipes. The reserved excess pipe length can cope with the damage of the water injection pipe caused by uneven settlement on the soil surface, and the steel hose 41 itself has a certain strength. It can withstand the pressure generated by the surrounding soil when laid inside the soil, ensuring the circulation of water inside the independent water injection pipes 4-1, 4-2, and 4-3, and will not affect the experimental results; the internal water injection pipes 4 are laid at different positions in the model box 14 to simulate different pressurized aquifers in actual conditions. The sizes and layout positions of the independent water injection pipes 4-1, 4-2, and 4-3 can be adjusted and laid according to actual conditions, and connected with the steel hose 41, which is convenient and efficient to use;

[0047] S4: After the test soil material and monitoring instruments are laid inside the model box 14, a pressure plate of the required size is added to the upper surface of the model box 14, and the upper surface of the pressure plate is connected to the top of the mechanical jack 5. At this time, the tops of the three mechanical jacks 5 arranged on the reaction beam 3 are simultaneously extended under the action of the pressure plate of the same size on the upper surface of the model box 14, and a quantitative pressure is applied to the test soil material inside the model box 14 to simulate the influence of the ground building load on the stratum deformation, such as Figure 6 The reaction beam 3 frame is welded to the model box 14 frame, and the bottom of the mechanical jack 5 is welded to the intersection of the reaction beam 3 frame after being inverted, so as to provide a good reaction support at the intersection;

[0048] S5: Simulation stage. In the process of simulating the injection of pressurized water, the first valve 10 on the pipe connecting the water storage tank 11 and the water pump 9 and the second valve 17 on the pipe connecting the water pumping pipe 13 and the rigid PVC pipe 42 can be opened, and the first valve 10 set on the pipe connecting the sedimentation tank 8 and the water pump 9 can be closed. The water storage tank 11 can provide a certain water pressure and water flow to the inside of the internal water injection pipe 4, so that the water flow can quickly fill the water pipe between the rigid PVC pipe 42 and the internal water injection pipe 4, and evenly inject water into the test soil material laid inside the model box 14 through the water hole 43 to form a pressurized aquifer;

[0049] S6: In the process of simulating ground subsidence induced by extraction of confined water, the first valve 10 on the pipe connecting the water storage tank 11 and the water pump 9 and the second valve 17 corresponding to the non-simulated pumped confined water aquifer can be closed, and the first valve 10 set on the pipe connecting the sedimentation tank 8 and the water pump 9 and the second valve 17 corresponding to the corresponding pumped confined water aquifer can be opened to discharge the simulated extracted confined water into the sedimentation tank 8, so that the amount of water extracted can be easily observed, and the fine sediment extracted with the water flow will also settle to the bottom of the sedimentation tank 8 for later water recycling;

[0050] S7: In the process of simulating the ground rebound induced by the injection of confined water, the first valve 10 on the pipe connecting the water storage tank 11 and the water pump 9 and the second valve 17 corresponding to the corresponding water-injected confined water aquifer can be opened, and the first valve 10 set on the pipe connecting the sedimentation tank 8 and the water pump 9 and the second valve 17 corresponding to the non-simulated water-injected confined water aquifer are closed. The water storage tank 11 can inject water into the internal water injection pipe 4, so that the water flow can quickly fill the rigid PVC pipe 42 and the water pipe of the internal water injection pipe 4, and evenly inject water into the test soil material through the water hole 43 to ensure the stable recovery of the water level of the confined water aquifer;

[0051] S8: Monitoring stage, the experimental data monitoring equipment is used to monitor the changes of the test soil material in the model box 14, and analyze the dynamic changes of ground settlement or rebound and pressure water level according to the change data of the test soil material.

[0052] Specifically, in step S1, the test soil material refers to the soil material of the simulated stratum set for each working condition of the experimental setting, and the test personnel can adjust its composition and proportion according to actual needs.

[0053] Specifically, in step S1, the experimental data monitoring equipment includes a soil pressure sensor, a moisture content meter, a pore water pressure sensor, an optical fiber strain monitoring, a layered marker settlement meter, a laser displacement meter and a camera. The monitoring devices of the soil pressure sensor, the moisture content meter, the pore water pressure sensor, the optical fiber strain monitoring and the layered marker settlement meter are buried inside the test soil material, the laser displacement meter is arranged on the upper surface of the test soil material, and the camera is arranged outside the model box 14.

[0054] The present invention is used to conduct large-scale physical model tests on the coupling effects of ground subsidence and rebound with groundwater level changes, to study the formation mechanism and evolution mechanism of ground subsidence and rebound under coupling conditions, to verify the effects of extracting confined groundwater and restoring confined groundwater on the formation and activity intensity of ground subsidence or rebound, and to improve the theoretical analysis of the causal mechanism of ground subsidence and rebound under the action of groundwater level changes.

[0055] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), installation arrangement, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of performing the function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to numerous modifications still falling within the scope of the appended claims.

[0056] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment may not be described (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention).

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A test device for simulating ground deformation caused by pressurized water extraction and reinjection, comprising a model box frame (1), a cross lift (12), a water pump (9), a sedimentation tank (8) and a model box (14), characterized in that: The inner wall of the model box frame (1) is fixedly connected to the organic tempered glass (2), the top of the model box frame (1) is fixedly connected to the reaction beam (3), and three mechanical jacks (5) are fixedly installed on the top of the inner side of the reaction beam (3). The inner side of the model box frame (1) is provided with a plurality of internal water injection pipes (4) which are evenly distributed, and a steel wire hose (41) is threadedly connected between two adjacent internal water injection pipes (4). The internal water injection pipes (4) close to the left and right sides of the inner cavity of the model box frame (1) are connected to rigid PVC pipes (42) at their terminals, and a water hole (43) is provided on the water pipe surface of the internal water injection pipe (4), and a water filter (44) is provided on the outer side of the water hole (43). A water storage tank (11) is fixedly installed on the top of the cross lift (12); the top of the water pump (9) is connected to the sedimentation tank (8) and the water storage tank (11) through pipelines, and the connected pipelines are respectively provided with a first valve (10); a rigid water pumping and injection pipe (13) is connected between one end of the water pump (9) and the rigid PVC pipe (42); a second valve (17) is provided on the rigid water pumping and injection pipe (13) near one end of the rigid PVC pipe (42); water outlets (15) are provided on the left and right sides of the model box frame (1); and ordinary pressure measuring pipes (70) and U-shaped pressure measuring pipes (7) connected to different aquifers are respectively threadedly connected near the water outlets (15) on the left and right sides of the model box frame (1).

2. The test equipment for simulating formation deformation caused by pressurized water extraction and reinjection according to claim 1 is characterized by: The internal water injection pipe (4) is made of rigid PVC as a whole, and two adjacent internal water injection pipes (4) can be disconnected or threadedly connected via a steel hose (41).

3. The test equipment for simulating formation deformation caused by pressurized water extraction and reinjection according to claim 1 is characterized by: The cross lift (12) comprises a lift base (121), a lift rail (122), a pulley (123), a lift cross bracket (124), a cross bracket connecting rod (125), and a lift top plate platform (126). The lift rail (122) is fixedly mounted on the front and rear ends of the top of the lift base (121); the pulley (123) is fixedly mounted on the left and right ends of the inner side of the lift rail (122); the lift cross bracket (124) is fixedly mounted on the upper end of the pulley (123); the cross bracket connecting rod (125) is movably connected to the inner side of the lift cross bracket (124); and the lift top plate platform (126) is fixedly mounted on the upper end of the lift cross bracket (124).

4. The test equipment for simulating formation deformation caused by pressurized water extraction and reinjection according to claim 1 is characterized by: An auxiliary ladder (6) is fixedly mounted on the left end of the front face of the model box frame (1).

5. The test equipment for simulating formation deformation caused by pressurized water extraction and reinjection according to claim 1 is characterized by: A pressure measuring tube fixing rod (16) fixedly connected to a common pressure measuring tube (70) is fixedly installed on the left side of the model box frame (1).

6. The test method for simulating formation deformation caused by confined water extraction and reinjection according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: S1: Experimental preparation stage, the model box (14) of the experimental equipment includes a base, a model box frame (1), organic tempered glass (2), an internal water injection pipe (4), a plurality of rigid water extraction and injection pipes (13), a water pump (9), a U-shaped pressure measuring tube (7), a common pressure measuring tube (70), a reaction beam (3), a mechanical jack (5), two sedimentation tanks (8), two water storage tanks (11), a cross lift (12) and experimental data monitoring equipment, wherein the model box (14) is directly placed on the ground, or a base can be separately provided and placed at the bottom of the model box frame (1) so that the model box (14) is off the ground, and the organic tempered glass (2) is arranged on the model box frame (1), and a layer of structural glue is applied on both the inner and outer surfaces of the contact surface between the two to ensure the overall sealing of the model box (14), and then, the test soil material is laid inside the model box (14); S2: When laying the test soil material into the model box (14) through the spaces on both sides of the reaction beam (3) at the top of the model box, firstly, large particles larger than the diameter of the water hole (43) are screened out, and a thin layer is laid on the upper and lower sides of the internal water injection pipe (4) respectively to play a filtering role, and together with the water filter (44) on the outside of the water pipe, the fine particles in the soil material are blocked from entering the internal water injection pipe (4), so as to ensure the smooth progress of the ground settlement rebound test caused by simulating the extraction of the confined aquifer and the recharging of groundwater; S3: When laying the test soil material, a detachable internal water injection pipe (4) is provided and laid at different heights to simulate multiple confined water aquifers at different layers, and each internal water injection pipe (4) can be connected to a water pump (9) through a rigid water extraction and injection pipe (13), so as to simulate the actual situation of extracting confined water at different depths; S4: After the test soil material and monitoring instruments are laid inside the model box (14), a pressure plate of the size required for the test is added to the upper surface of the model box (14), and the upper surface of the pressure plate is connected to the top of the mechanical jack (5). At this time, the tops of the three mechanical jacks (5) arranged on the reaction beam (3) are simultaneously extended under the action of the pressure plates of the same size on the upper surface of the model box (14), and a quantitative pressure is applied to the test soil material inside the model box (14), so as to simulate the influence of the ground building load on the stratum deformation; S5: Simulation stage. In the process of simulating the injection of pressurized water, the first valve (10) on the pipe connecting the water storage tank (11) and the water pump (9) and the second valve (17) on the pipe connecting the water pumping pipe (13) and the rigid PVC pipe (42) can be opened, and the first valve (10) provided on the pipe connecting the sedimentation tank (8) and the water pump (9) can be closed. The water storage tank (11) can provide a certain water pressure and water flow to the inside of the internal water injection pipe (4), so that the water flow can quickly fill the water pipe between the rigid PVC pipe (42) and the internal water injection pipe (4), and evenly inject water into the test soil material laid inside the model box (14) through the water hole (43), so as to form a pressurized aquifer. S6: In the process of simulating ground subsidence induced by extraction of confined water, the first valve (10) on the pipe connecting the water storage tank (11) and the water pump (9) and the second valve (17) corresponding to the non-simulated pumped confined water aquifer can be closed, and the first valve (10) provided on the pipe connecting the sedimentation tank (8) and the water pump (9) and the second valve (17) corresponding to the corresponding pumped confined water aquifer can be opened to discharge the simulated extracted confined water into the sedimentation tank (8), so that the amount of water extracted can be easily observed, and the fine sediment extracted along with the water flow will also settle to the bottom of the sedimentation tank (8) for later water recycling; S7: In the process of simulating the ground rebound induced by the injection of pressurized water, the first valve (10) on the pipe connecting the water storage tank (11) and the water pump (9) and the second valve (17) corresponding to the corresponding water-injected pressurized water aquifer can be opened, and the first valve (10) provided on the pipe connecting the sedimentation tank (8) and the water pump (9) and the second valve (17) corresponding to the non-simulated water-injected pressurized water aquifer can be closed. The water storage tank (11) can inject water into the internal water injection pipe (4), so that the water flow can quickly fill the water pipe between the rigid PVC pipe (42) and the internal water injection pipe (4), and evenly inject water into the test soil material through the water hole (43), so as to ensure the stable recovery of the water level of the pressurized water aquifer; S8: During the monitoring phase, the experimental data monitoring equipment is used to monitor the changes in the test soil material in the model box (14), and analyze the dynamic changes in ground settlement or rebound and pressure water level based on the change data of the test soil material.

7. A test method for simulating dynamic changes of multi-layer pressure water level according to claim 6, characterized in that: In step S1, the test soil material refers to the soil material of the simulated stratum set for each working condition of the experimental setting, and the test personnel can adjust its composition and proportion according to actual needs.

8. A test method for simulating dynamic changes of multi-layer pressure water level according to claim 6, characterized in that: The experimental data monitoring equipment in step S1 includes a soil pressure sensor, a moisture content meter, a pore water pressure sensor, an optical fiber strain monitoring, a layered standard settlement meter, a laser displacement meter and a camera. The monitoring devices of the soil pressure sensor, the moisture content meter, the pore water pressure sensor, the optical fiber strain monitoring and the layered standard settlement meter are buried inside the test soil material, the laser displacement meter is arranged on the upper surface of the test soil material, and the camera is arranged outside the model box (14).

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