Groundwater infiltration simulation control method for geotechnical environment simulation test

Abstract

The application discloses a groundwater infiltration simulation control method for rock-soil environment simulation test, characterized in that one side of a simulated soil in a test area in a simulation box is separated from an independent water collecting area by a movable retaining wall, groundwater simulation water is first connected to the water collecting area, then the retaining wall is lifted upwards to expose a required interval of the groundwater simulation depth, and water flows into the simulated soil from the interval according to the exposed height, thereby forming the required groundwater simulation depth. The application can better control and realize the simulation of the groundwater infiltration into the soil, better assist the simulation and reduction of the soil environment in the soil freeze-thaw test, and improve the simulation accuracy and application range of the soil freeze-thaw test.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of freeze-thaw soil related performance research, and particularly relates to a groundwater infiltration simulation control method for geotechnical environment simulation test. BACKGROUND

[0002] Land freezing and thawing refers to a physical geological action and phenomenon that the soil layer freezes and thaws due to the temperature falling below zero and rising above zero. Due to the large seasonal and diurnal temperature difference, the surface soil in the eastern and western regions of China is usually in a freeze-thaw environment in stages. Under the freeze-thaw environment, groundwater is usually formed in the land, and in the freezing process, the water in the soil freezes into ice and generates many ice inclusions and ice mirror bodies, causing the relative displacement of soil particles and the expansion of the soil body. This phenomenon is called frost heaving. The external appearance of frost heaving is the uniform or non-uniform bulging, bulging, cracking, etc. of the soil layer, and obvious subsidence occurs after thawing, which causes great damage to the structure. Generally speaking, when the water in the soil freezes, the volume increases by about 9%, causing the ground soil to expand outward. Therefore, under the repeated freezing and thawing action, great damage is caused to the rock mass in the soil layer and the concrete building foundation, etc. The former is prone to accidents such as landslides and landslides after damage, and the latter directly affects the safety performance of the building. Therefore, it is necessary to study the damage caused by freeze-thaw soil in the field of soil engineering in the freeze-thaw area; especially to study and explore the damage effect of freeze-thaw soil on the structure under the action of groundwater. However, some existing freeze-thaw test methods, such as the load and multi-environment factor coupling concrete durability test device disclosed in CN114486512A, the soil erosion test device and test method considering multi-factor coupling disclosed in CN202210056257.3, etc. cannot simulate the situation of soil body under the action of groundwater infiltration, which affects the application range of the test.

[0003] Therefore, it is necessary to design a method that can better control and realize the simulation of groundwater infiltration to the soil body, so as to better assist the simulation and restoration of the soil body environment in the freeze-thaw test and improve the simulation accuracy and application range of the freeze-thaw test of the soil body. SUMMARY

[0004] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present application is: how to provide a groundwater infiltration simulation control method for geotechnical environment simulation test, which can better control and realize the simulation of groundwater infiltration to the soil body; so as to better assist the simulation and restoration of the soil body environment in the freeze-thaw test and improve the simulation accuracy and application range of the freeze-thaw test of the soil body.

[0005] In order to solve the above technical problems, the present application adopts the following technical scheme:

[0006] The application discloses a groundwater infiltration simulation control method for a geotechnical environment simulation test.

[0007] Thus, the depth of the groundwater infiltration in the simulation soil can be better controlled, the simulation and restoration of the soil environment in the soil freeze-thaw test are better assisted, and the simulation accuracy and application range of the soil freeze-thaw test are improved.

[0008] Further, when the simulation box is used to simulate a depth lower than the required simulation groundwater depth, the simulation box is closed and gas is introduced to pressurize the simulation box, the water pressure at the bottom of the simulation box is detected, the water pressure is made consistent with the pressure of the required simulation groundwater depth, and deeper groundwater depth simulation is realized.

[0009] Thus, a smaller simulation box can be better used to realize deeper groundwater depth simulation, and the simulation application range is better improved.

[0010] Further, the method is realized by using a groundwater depth adjusting simulation device, the groundwater depth adjusting simulation device comprises a water collecting groove arranged on the inner side of the side wall of the simulation box where the water conveying pipeline is located, the water collecting groove is arranged along the whole length direction of the side wall of the simulation box where the water conveying pipeline is located, the upper surface of the water collecting groove is not lower than the height of the test piece positioning device, the side wall of the water collecting groove facing the test piece positioning device is integrally arranged as a movable side wall, the movable side wall is slidably clamped and matched in the side wall sliding groove on both sides of the movable side wall, and the movable side wall is connected with a side wall up-down moving control mechanism.

[0011] Thus, when water is input into the water conveying pipeline to simulate the groundwater, the water can be first conveyed into the water collecting groove, and then the movable side wall is controlled to be integrally lifted to a preset groundwater depth position, so that the water in the water collecting groove flows out from the fixed height position below the movable side wall to form the groundwater. The groundwater simulation is more convenient and reliable, and the groundwater depth accuracy can be better controlled and is more accurate.

[0012] Further, the side of the movable side wall facing the test piece positioning device is further sequentially provided with a support grid and a sponge material fixed on the support grid. Thus, the movable side wall can be prevented from being controlled to lift up due to the sand soil entering the water collecting groove, and the water in the water collecting groove can flow out without being hindered. Meanwhile, the impact of the direct water flow in the water collecting groove on the sand soil can be avoided to affect the test.

[0013] Further, the baffle wall up-down movement control mechanism comprises baffle wall racks fixed vertically at both ends of the moving baffle wall on one side, two baffle wall racks are respectively engaged with a baffle wall control gear at the same horizontal height, two baffle wall control gears are fixed on a baffle wall control shaft arranged horizontally, both ends of the baffle wall control shaft are rotatably installed on the simulation box and one end of the baffle wall control shaft is arranged outside the simulation box and provided with a baffle wall control rotary handle.

[0014] In this way, the moving baffle wall can be conveniently moved up and down along the baffle wall sliding groove by rotating the baffle wall control rotary handle, engaging the baffle wall control gears with the baffle wall racks. The structure is simple, stable and reliable.

[0015] Further, the simulation box side located at the position of the moving baffle wall is provided with a scale. In this way, the height value of the moving baffle wall being lifted up can be directly observed, so as to conveniently and accurately control the depth of the groundwater discharge.

[0016] Further, the groundwater depth adjusting simulation device further comprises a water baffle located on the side of the simulation box away from the water pipeline direction and arranged in parallel and spaced apart on the same side, both ends of the water baffle are slidably clamped and matched in the water baffle sliding groove of the inner side wall of the simulation box, the bottom of the simulation box below the water baffle is provided with a water baffle sink, the water baffle is connected with a water baffle up-down movement control mechanism, the water baffle up-down movement control mechanism can control the water baffle to extend upward or retract downward into the water baffle sink, after the water baffle extends upward, a drainage cavity is formed on the side away from the water pipeline direction, and a drainage pipeline is arranged on the bottom surface of the drainage cavity.

[0017] In this way, when simulating underground water, the baffle can be first controlled to extend upward to the position of the depth of the underground water to be simulated (or 1-5 cm lower than the depth of the underground water to be simulated, so as to offset the water level of the part of the baffle overflowing in the test area). When the water in the tank reaches the height of the baffle, it can flow over the baffle into the drainage cavity and be discharged from the drainage pipeline. In this way, the depth of the underground water in the test area can be better ensured to meet the simulation requirements. In addition, from the above process, it can be seen that when the baffle and the baffle wall are used together, the outflow depth of the water in the water collecting tank is controlled by the baffle wall, and the depth of the water infiltration in the test area is ensured to meet the requirements by the baffle. Therefore, the simulation of the depth of the underground water can be better realized. More specifically, during the freeze-thaw cycle test, when the underground water is in the frozen state, the operation is relatively simple, and the water supply pipeline only needs to be closed. However, when the underground water is in the thawed state, since the freeze-thaw area is usually a mountainous environment, the underground water is usually in a slow flowing state after thawing. Therefore, when the baffle and the baffle wall are used together, the height of the upper end of the baffle is controlled to be lower than the interval height (i.e. the depth of the underground water to be simulated) between the lower end of the baffle wall by a distance (which can usually be 1-5 cm), and the water supply pipeline is opened to supply water according to the actual flow rate and flow of the underground water to be simulated. In this way, the slow flowing state of the underground water can be better simulated while ensuring that the depth of the underground water is maintained. Especially when the depth of the underground water simulation in the simulation tank is not enough and the air pressure needs to be increased in the simulation tank to increase the depth of the underground water simulation, the baffle wall and the baffle can be used together to better ensure that the underground water in the area between the baffle and the baffle wall can be pressed by the increased air pressure, so that the bottom of the test area can form a stronger water pressure effect, and the role of increasing the simulation water depth by air pressure can be better played. In addition, when the air pressure is increased for simulation, the drainage pipeline can be closed to avoid air leakage when the air pressure is high. At this time, the baffle can also be used to form a drainage cavity area to store water and meet the needs of the test area for underground water simulation.

[0018] Further, the side of the baffle facing the water supply pipeline is further outwardly fixed with a support grid and a sponge material fixed on the support grid.

[0019] In this way, the sand can be prevented from entering and affecting the lifting control of the baffle, but the water flow is not hindered. At the same time, the test sand can also be prevented from being washed away by the water flow and affecting the test.

[0020] Furthermore, the water baffle moving up and down control mechanism includes water baffle racks vertically fixed at both ends of one side of the water baffle. The two water baffle racks respectively mesh with a water baffle control gear located at the same horizontal height. The two water baffle control gears are fixed on a water baffle control shaft set at the same horizontal level. The two ends of the water baffle control shaft are rotatably mounted on the simulation box, and one end extends out of the simulation box and is provided with a water baffle control rotating handle.

[0021] This design allows for easy control of the baffle plate by rotating the control handle. The engagement of the control gear and the baffle plate rack drives the baffle plate to move up and down along its groove. The structure is simple, stable, and reliable.

[0022] Furthermore, a scale is installed on the side of the simulation chamber at the location of the water baffle. This allows for a direct visual indication of the height to which the water baffle is lifted, facilitating precise control of the groundwater depth.

[0023] Furthermore, the groundwater depth regulation simulation device also includes a sealing strip and a top cover pressing and sealing mechanism installed between the top cover and the body of the simulation box, as well as a water pressure detection sensor located at the bottom of the simulation box and a gas pressure delivery pipe connected to the simulation box, the gas pressure delivery pipe being connected to a gas compressor outside the simulation box.

[0024] In this way, when the simulation chamber cannot accurately simulate the depth of groundwater, the top cover can be sealed using a sealing strip and a top cover clamping mechanism. Then, air pressure is introduced into the simulation chamber via a pneumatic compressor and air supply pipeline. Under the combined action of air and water pressure, the water pressure at the bottom of the simulation chamber is detected by a water pressure sensor, ensuring it matches the actual groundwater pressure at the bottom of the building's foundation concrete. This maintains the freeze-thaw cycle test under realistic water pressure conditions, simulating deeper groundwater infiltration and thus expanding the scope of experimental applications. The top cover clamping mechanism can be implemented using existing mechanisms such as bolt fixing or quick-connect clip fixing; the specific structure is not detailed here.

[0025] In summary, this invention can better control and realize the simulation of groundwater infiltration in soil, thereby better assisting the soil freeze-thaw test in simulating and restoring the soil environment, and improving the simulation accuracy and application scope of the soil freeze-thaw test. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a rock mass freeze-thaw cycle test system used in a specific implementation.

[0027] Figure 2 for Figure 1 A schematic diagram of the structure of a standalone groundwater depth regulation simulation device.

[0028] Figure 3 For Figure 1 Structure diagram of the control mechanism moving up and down from the side direction of the retaining wall.

[0029] Figure 4 For Figure 1 Structure diagram of the control mechanism moving up and down from the side direction of the retaining wall.

[0030] Figure 5 For Figure 1 Structure diagram of the separate pressure device. DETAILED DESCRIPTION

[0031] Since the present application is used for simulating underground water in the freezing and thawing simulation test of soil environment, in the detailed description, the present application is introduced in combination with a foundation concrete freezing and thawing cycle test method. The present application is used for simulating underground water in the method. The introduction of the present application in combination with the foundation concrete freezing and thawing cycle test method can better reflect the role and significance of the present application in the simulation of underground water.

[0032] The present application is further described in detail in combination with a foundation concrete freezing and thawing cycle test method.

[0033] Detailed description: a foundation concrete freezing and thawing cycle test method, wherein a corresponding concrete test piece is prepared according to the performance requirements of the building foundation concrete to be tested, the concrete test piece is fixed in a simulation box, the construction environment of the building foundation concrete is simulated, the concrete test piece is buried in the simulated soil material, the actual underground water immersion of the building foundation concrete is simulated by infiltrating water into the lower part of the simulation box, the pressure is applied to the concrete test piece according to the bearing size of the building foundation concrete (which can be obtained by calculation), and the preparation work is completed; during the test, the infiltrated water is cooled to form ice by passing cold air, the ice is heated to complete thawing by applying electric heating radiation above the concrete test piece, and the freezing and thawing cycle is formed by repeating the above steps, until the freezing and thawing test time ends, the concrete test piece is taken out and its performance is tested, and the performance change parameters of the building foundation concrete affected by the freezing and thawing environment are obtained by comparing with the same concrete test piece without test.

[0034] The above test method better simulates the situation of the building foundation concrete structure being buried by soil and being infiltrated by groundwater. At the same time, it simulates the actual freezing and thawing situation of the building foundation concrete, which is blown by cold wind at night to form ice and is irradiated by sunlight during the day to complete thawing. It can better simulate the actual freezing and thawing situation of the building foundation concrete. The performance parameter changes obtained after the test can better reflect the influence of the actual freezing and thawing situation on the performance. It can be better used for safety monitoring or pre-construction safety performance evaluation of the building foundation concrete, thereby improving the safety of the building.

[0035] During the test, the temperature of the test environment cooled by the cold wind is determined by the lowest temperature of the building foundation concrete in the local spring and autumn season at night.

[0036] In this way, extreme environmental parameters are simulated, and the test results can be better used for safety evaluation.

[0037] During the test, the temperature of the heating by electric heating radiation is determined by the highest temperature of the building foundation concrete in the local spring and autumn season during the day.

[0038] In this way, extreme environmental parameters are simulated, and the test results can be better used for building safety evaluation.

[0039] When preparing the concrete test piece, the building foundation concrete to be tested is poured into a cylindrical test piece according to the same concrete formula.

[0040] In this way, the test results of the concrete test piece can better reflect the actual performance changes of the building foundation concrete affected by freezing and thawing, thereby improving the reliability of the test.

[0041] During the test, the simulated soil material is prepared by using gravel, sand and clay materials to simulate the actual soil around the building foundation concrete. A better choice is to directly excavate the actual soil around the building foundation concrete to obtain the simulated soil material, which contains corresponding microorganisms to maintain the consistent influence of rock microorganisms on the concrete.

[0042] In this way, the actual situation can be better simulated, and the reliability of the test can be improved.

[0043] During the test, when the depth of the simulation box (referring to the depth available for the test) is greater than the depth of the building foundation concrete to be tested that is infiltrated by groundwater, the depth of the water infiltrated into the lower part of the simulation box is consistent with the actual depth of the groundwater infiltration. When the depth of the simulation box (referring to the depth available for the test) is less than the depth of the building foundation concrete to be tested that is infiltrated by groundwater, the simulation box is sealed and gas is introduced to pressurize it. The water pressure at the bottom of the simulation box is detected to be consistent with the actual water pressure at the lowest point of the building foundation concrete to be tested (the actual water pressure value can be obtained by actual detection or calculation).

[0044] Thus, when the building foundation concrete to be tested is deeply infiltrated by underground water, a smaller simulation box can be used to simulate the deep underground water infiltration, greatly improving the application range of the test. When the test is simulated by applying pressure, the height of the concrete test piece can be set to be the same as the testable depth of the simulation box, and then the simulation soil material is covered to the same height as the concrete test piece. Then, the depth of the water infiltrated into the lower part of the simulation box is retained to have 5-10 cm of non-infiltrated soil material above, which better simulates the actual situation of the concrete test piece being infiltrated by underground water.

[0045] Specifically, the time of one freeze-thaw cycle is 24 hours, including freezing for 12 hours and thawing for 12 hours; the number of freeze-thaw cycles is set to be 7, 15, 30, 60 or 90 times according to the research, and the corresponding time is 7, 15, 30, 60 or 90 days.

[0046] This is because it is difficult to reflect the change situation if it is less than seven days. If it is more than 90 days, the time is too long and it is difficult to have a test significance. After the freeze-thaw test is completed within a limited time, the performance change situation of the concrete test piece can be obtained by detecting the performance parameters of the concrete test piece, and the performance change situation caused by freeze-thaw action for more time can be reasonably calculated to guide the actual safety monitoring.

[0047] Among them, after the freeze-thaw test time is over, the concrete test piece is taken out, and uniaxial compression test or triaxial compression test is carried out on it to test the mechanical properties of the concrete test piece after being subjected to freeze-thaw cycles, including compressive strength and elastic modulus parameters, and the mechanical properties of the concrete test piece without freeze-thaw are compared to obtain the degradation degree of the mechanical properties of the building foundation concrete affected by the freeze-thaw environment.

[0048] In specific implementation, the above test method is implemented by relying on Figures 1-5 A freeze-thaw cycle test system for building foundation concrete as shown in the figure is implemented, which comprises a simulation box 1, the upper end of the simulation box 1 is provided with an openable top cover 2, the middle and lower part of the simulation box 1 is provided with a test piece positioning device, and a pressure applying device is further provided opposite above the positioning device; a water conveying pipeline 4 with a switch valve is communicated to one side of the middle and lower part of the side of one end of the simulation box 1, the other end of the water conveying pipeline 4 is connected with a water storage tank 5, and a water drainage pipeline 6 with a switch valve is communicated downward to the position of the bottom surface of the other end of the simulation box 1; a refrigeration evaporator 7 is further arranged at the upper part of the simulation box, the refrigeration evaporator 7 has a built-in fan and has an air inlet and an air outlet forming an internal circulation in the simulation box chamber, the refrigeration evaporator 7 is connected with a compressor 8 arranged outside the simulation box to form a refrigeration cycle system; an electric heating tube 9 is further fixed to the inner surface of the top cover of the simulation box; and a groundwater depth adjusting and simulating device for adjusting and simulating the groundwater depth in the simulation box is further included.

[0049] Thus, in the aforementioned apparatus, the specimen positioning device facilitates the temporary positioning of concrete specimens to simulate soil burial, the pressure application device applies pressure to the concrete specimens to simulate actual pressure conditions, the water tank and drainage pipes facilitate the injection and discharge of simulated groundwater, and the groundwater depth adjustment device controls and adjusts the groundwater depth to match the actual situation. A refrigeration cycle system provides cooling and freezing to the simulation chamber, and an electric heating tube thaws the frozen soil through electrothermal radiation, thus better simulating the actual freeze-thaw conditions of building concrete foundations. Therefore, the above-mentioned experimental system is well-suited for the aforementioned simulation test methods, is simple, reliable, and effective in operation, and can significantly improve the convenience and simulation effect of the experiment, as well as the accuracy of the test results.

[0050] The specimen positioning device includes a positioning ring 10 located in the middle. The inner diameter of the positioning ring 10 is 1-10 mm larger than the outer diameter of the specimen. The periphery of the positioning ring is fixed to the inner wall of the simulation chamber by horizontally set fixing rods. This structure is simple and facilitates the placement and positioning of the specimen.

[0051] The pressure device includes a pressure head 11 positioned above the positioning ring. The pressure head 11 is connected to a hydraulic tank 12 via a retractable pressure rod. The hydraulic tank 12 is fixedly mounted on the inner wall of the simulation box 1 via a support arm 13. The hydraulic tank 12 is connected to a control oil tank 3 outside the simulation box via hydraulic pipes.

[0052] This allows for easy control of the hydraulic tank via the oil tank, enabling the pressure head to extend downwards and apply pressure to the concrete specimen positioned within the positioning ring, thus simulating its actual working stress conditions.

[0053] The lower surface of the pressure head 11 is equipped with a specimen pressure detection sensor 14, which facilitates the detection of the magnitude of the pressure applied to the concrete specimen.

[0054] The upper surface of the drainage pipe is equipped with a mesh screen. This prevents mud and sand from leaking out with the water during drainage.

[0055] The system includes four evaporators positioned at the four corners of the top of the simulation chamber. This ensures faster and more even cooling.

[0056] The simulation chamber 1 is made of transparent material. This allows for easy observation of the test conditions inside the simulation chamber.

[0057] The simulation chamber 1 is equipped with a vertical scale 15 on at least one side. This facilitates the observation of the groundwater level.

[0058] The groundwater depth adjusting simulation device comprises a water collecting tank 16 arranged on the inner side of the side wall of the simulation box in which the water pipeline is arranged, the water collecting tank 16 is arranged along the whole length direction of the side wall of the simulation box in which the water pipeline is arranged, the upper surface of the water collecting tank is not lower than the height of the test piece positioning device, the stop wall on the side of the water collecting tank facing the test piece positioning device is integrally arranged as a movable stop wall 17, the movable stop wall 17 is slidably connected to the stop wall sliding groove 18 on both sides, and the movable stop wall 17 is connected with a stop wall up-down moving control mechanism.

[0059] In this way, when the water pipeline inputs water to simulate groundwater, the water can be first delivered to the water collecting tank, and then the movable stop wall is controlled to be lifted to a preset groundwater depth position, so that the water in the water collecting tank flows out from the fixed height position below the movable stop wall to form groundwater. The simulated groundwater is more convenient and reliable, and the groundwater depth precision can be better controlled and accurate.

[0060] The side of the movable stop wall 17 facing the test piece positioning device is further sequentially provided with a support grid 19 and a sponge material fixed on the support grid. In this way, the sand can be isolated from entering the water collecting tank to affect the lifting control of the movable stop wall, but the water in the water collecting tank can still flow out. At the same time, the impact of the direct water flow in the water collecting tank on the sand can also be avoided to affect the test.

[0061] The stop wall up-down moving control mechanism comprises a stop wall rack 20 fixed vertically on both ends of the side of the movable stop wall, two stop wall racks 20 are respectively engaged with a stop wall control gear 21 at the same horizontal height, the two stop wall control gears 21 are fixed on a stop wall control shaft 22 arranged horizontally, both ends of the stop wall control shaft 22 are rotatably installed on the simulation box and one end of the stop wall control shaft 22 penetrates the simulation box and is provided with a stop wall control rotating handle 23.

[0062] In this way, the stop wall control rotating handle can be conveniently rotated to drive the movable stop wall to move up and down along the stop wall sliding groove through the engagement of the stop wall control gear and the stop wall rack. The structure is simple and stable and reliable.

[0063] The scale arranged on the side of the simulation box is located at the position of the movable stop wall. In this way, the height value of the movable stop wall being lifted up can be directly observed to facilitate the accurate control of the depth of the groundwater discharge.

[0064] The underground water depth adjusting simulation device comprises a water baffle 25 located on the side of the simulation box away from the water pipeline and parallelly spaced apart from the side, both ends of the water baffle 25 being slidably clamped in the water baffle sliding groove 26 of the inner side wall of the simulation box, the bottom of the simulation box below the water baffle 25 being provided with a water baffle sink 27, the water baffle 26 being connected with a water baffle up-down moving control mechanism, the water baffle up-down moving control mechanism being capable of controlling the water baffle to extend upward or retract downward in the water baffle sink 27, a drainage cavity being formed on the side away from the water pipeline after the water baffle extends upward, and a drainage pipeline being arranged on the bottom surface of the drainage cavity.

[0065] In this way, when simulating underground water, the water baffle can be controlled to extend upward to the underground water depth position to be simulated (or 1-5 cm lower than the underground water depth to be simulated, so as to offset the water level height of the water overflowing the water baffle in the test area). When the water in the simulation box reaches the height of the water baffle, the water can flow over the water baffle into the drainage cavity and be discharged from the drainage pipeline. In this way, the underground water depth in the test area can better meet the simulation requirements. In addition, from the above process, it can be seen that when the water baffle and the water retaining wall are used together, the water outflow depth in the water collecting tank is controlled by the water retaining wall, the water baffle is used to retain water and ensure that the water infiltration depth in the test area meets the requirements, so that the simulation of the underground water depth can be better realized. More specifically, during the freeze-thaw cycle test, when the underground water is in the frozen state, the operation is relatively simple, and the water pipeline only needs to be closed. However, when the underground water is in the thawed state, since the freeze-thaw area is usually a mountainous environment, the underground water is usually in a slow flowing state after thawing. Therefore, when the water baffle and the water retaining wall are used together, the height of the upper end of the water baffle is controlled to be lower than the interval height (i.e. the underground water depth to be simulated) between the lower end of the water retaining wall by a distance (which can usually be 1-5 cm), and the water pipeline is opened to supply water according to the actual flow rate and flow of the underground water to be simulated. In this way, the slow flowing state of the underground water can be better simulated while ensuring that the underground water depth is sufficient. Especially when the underground water simulation depth of the simulation box is not sufficient and the air pressure needs to be increased to increase the underground water simulation depth, the water retaining wall and the water baffle can be used together to better ensure that the underground water depth is sufficient and the slow flowing state is simulated under the condition of increasing the air pressure (the water flow will not be pressed away by the high pressure). At the same time, the increased air pressure can better press the underground water in the area between the water baffle and the water retaining wall, so that the bottom of the test area can better form a stronger water pressure effect, and better play the role of increasing the simulation water depth by air pressure. In addition, when the air pressure is increased to strengthen the simulation, the drainage pipeline can be closed to avoid air leakage when the air pressure is high. At this time, the water baffle can be used to form a drainage cavity to store water and meet the needs of the test area for the simulation of the slow flow.

[0066] The water baffle 25 is provided with a support grid 28 and a sponge material fixed on the support grid outwardly in sequence on the side facing the water pipeline.

[0067] In this way, the sand can be prevented from entering and affecting the lifting control of the water baffle, but the water flow is not hindered. Meanwhile, the sand used for the test can be prevented from being washed away by the water flow and affecting the test.

[0068] The water baffle up-down movement control mechanism comprises water baffle racks 29 fixed vertically on both ends of the side of the water baffle, two water baffle control gears 30 at the same horizontal height and engaged with the water baffle racks 29 respectively, a water baffle control rotating shaft 31 provided horizontally and fixed with the two water baffle control gears 30, and a water baffle control rotating handle 32 provided on one end of the water baffle control rotating shaft 31 and protruding out of the simulation box.

[0069] In this way, the water baffle can be moved up and down along the water baffle sliding groove by rotating the water baffle control rotating handle, engaging the water baffle control gears with the water baffle racks. The structure is simple, stable and reliable.

[0070] The simulation box side surface is provided with a scale at the position of the water baffle. In this way, the height value of the water baffle being lifted up can be directly observed, so that the depth of the groundwater can be controlled accurately.

[0071] The groundwater depth adjusting simulation device further comprises a sealing strip and a top cover pressing sealing mechanism 35 installed between the top cover 2 and the box body 1 of the simulation box, a water pressure detection sensor (not shown in the figure) at the bottom of the simulation box, and a gas pressure delivery pipeline 36 connected to the simulation box and connected to a gas pressure machine (not shown in the figure) outside the simulation box.

[0072] In this way, when the simulation box cannot simulate the depth of the groundwater, the top cover can be pressed tightly by the sealing strip and the top cover pressing sealing mechanism to realize the sealing of the simulation box. Then, the gas pressure machine and the gas pressure delivery pipeline are used to input the gas pressure into the simulation box. Under the joint action of the gas pressure and the water pressure, the water pressure at the bottom of the simulation box is detected by the water pressure detection sensor, so that the water pressure at the bottom of the building foundation concrete to be tested is consistent with the actual underground water pressure, and the freeze-thaw cycle test is completed under the water pressure consistent with the actual situation, and the simulation of the deeper groundwater infiltration is completed. The application range of the test is better expanded. The top cover pressing sealing mechanism can be realized by existing mechanisms such as bolt fixation or quick-connection buckle fixation, and the specific structure is not described here.

[0073] More specifically, when the above test system is used for specific tests (for example, when the groundwater depth meets the simulation depth of the simulation box), first, open the top cover of the simulation box, then position the prepared concrete test piece vertically in the simulation box by the test piece positioning device, maintain the vertical positioning of the concrete test piece, control the pressure head to extend downward and be pressed on the upper end of the concrete test piece until the detection pressure reaches the test pressure; then, cultivate the simulation soil material into the simulation box until the concrete test piece is buried around. Then, adjust the water baffle to extend upward from the water baffle sink to 0-5 cm below the preset water depth; then open the switch valve on the water pipeline to inject water in the water storage tank into the water collecting tank, control the moving baffle of the water collecting tank to lift up to the lower end to expose to the preset water depth position, so that the water in the water collecting tank flows out from the lower end, until the water flows over the water baffle and flows to the drain pipe, then close the water pipeline, and then close the drain pipe when the water surface in the water collecting tank drops to the height position of the lower end of the moving baffle. Control the refrigeration cycle system to open to refrigerate the inside of the simulation box, so that the simulation soil material forms permafrost, then maintain the temperature in the simulation box as the lowest temperature of the building foundation concrete at night in the local spring and autumn season, until the freezing time ends (usually 12 hours); then close the refrigeration cycle system and open the electric heating pipe to heat, so that the temperature in the simulation box rises to thaw, and maintain the temperature in the simulation box at the highest temperature of the building foundation concrete in the local spring and autumn season during the day, until the thawing time ends (usually 12 hours); then repeat the freeze-thaw cycle until the test days end; then open the top cover of the simulation box, take out the concrete test piece and test its performance to obtain the performance change parameter characteristics.

Claims

1. A groundwater infiltration simulation control method for a geotechnical environment simulation test, characterized by, One side of the soil body in the test area of the simulation box is separated from an independent catchment area by a movable retaining wall. The underground water simulation water is first introduced into the catchment area, and then the retaining wall is lifted up to expose the required underground water depth interval at the lower end, so that the water flows into the soil body according to the exposed height of the interval, and the underground water simulation of the required depth is formed. The method is realized by a groundwater depth adjusting simulation device. The device comprises a catchment tank arranged on the inner side of the side wall of the simulation box where the water supply pipeline is located. The catchment tank is arranged along the overall length direction of the side wall of the simulation box where the water supply pipeline is located. The upper surface of the catchment tank is not lower than the height of the test piece positioning device. The retaining wall on the side of the catchment tank facing the test piece positioning device is movably arranged. The retaining wall is movably connected with a retaining wall up-down movement control mechanism. The retaining wall up-down movement control mechanism comprises retaining wall racks fixed vertically on both ends of the side of the movable retaining wall. The two retaining wall racks are respectively engaged with a retaining wall control gear at the same horizontal height. The two retaining wall control gears are fixed on a retaining wall control shaft arranged horizontally. The two ends of the retaining wall control shaft are rotatably mounted on the simulation box, and one end of the retaining wall control shaft penetrates through the simulation box and is provided with a retaining wall control rotating handle. The groundwater depth adjusting simulation device further comprises a water baffle arranged on the side of the simulation box away from the water supply pipeline and parallel to the side. The two ends of the water baffle are movably connected with a water baffle sliding groove in the inner side wall of the simulation box. The bottom of the simulation box below the water baffle is provided with a water baffle sink. The water baffle is connected with a water baffle up-down movement control mechanism. The water baffle up-down movement control mechanism can control the water baffle to extend upward or retract downward into the water baffle sink. After the water baffle extends upward, a drainage cavity is formed on the side away from the water supply pipeline. A drainage pipeline is arranged on the bottom surface of the drainage cavity.

2. The groundwater infiltration simulation control method for a geotechnical environment simulation test according to Claim 1, wherein When the simulation depth of the simulation box is lower than the required underground water depth, the simulation box is closed and pressurized with gas. The water pressure at the bottom of the simulation box is detected to be consistent with the pressure of the required underground water depth, so that a deeper underground water depth simulation is realized.

3. The groundwater infiltration simulation control method for a geotechnical environment simulation test according to claim 1, wherein The side of the simulation box where the movable retaining wall is located is further provided with a support grid and a sponge material fixed on the support grid.

4. The groundwater infiltration simulation control method for a geotechnical environment simulation test according to Claim 1, wherein The side of the simulation box where the movable retaining wall is located is provided with a scale.

5. The groundwater infiltration simulation control method for a geotechnical environment simulation test according to Claim 1, wherein The side of the simulation box where the movable retaining wall is located is further provided with a support grid and a sponge material fixed on the support grid.

6. The groundwater infiltration simulation control method for a geotechnical environment simulation test according to claim 1, wherein The water baffle up-down movement control mechanism comprises water baffle racks fixed vertically on both ends of the side of the water baffle. The two water baffle racks are respectively engaged with a water baffle control gear at the same horizontal height. The two water baffle control gears are fixed on a water baffle control shaft arranged horizontally. The two ends of the water baffle control shaft are rotatably mounted on the simulation box, and one end of the water baffle control shaft penetrates through the simulation box and is provided with a water baffle control rotating handle. The side of the simulation box where the movable retaining wall is located is provided with a scale.

7. The groundwater infiltration simulation control method for a ground mass environment simulation test according to Claim 1, wherein The groundwater depth adjustment simulation device further comprises a sealing strip and a top cover pressing sealing mechanism installed between the simulation box top cover and the box body, and a water pressure detection sensor located at the bottom of the simulation box and a gas pressure delivery pipeline communicated with the simulation box, the gas pressure delivery pipeline being connected with a gas pressure machine outside the simulation box.

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