Device and method for testing residual strength of moraine soil

Abstract

The invention provides a moraine soil residual strength testing device which comprises a sample shearing box, a shearing assembly, a temperature adjusting part and a simulation pipe group, and the sample shearing box comprises two box bodies which are stacked up and down. The shearing assembly comprises a pushing part and shear stress detection equipment, the pushing part is connected to one box body, the shear stress detection equipment is connected to the other box body, the simulation pipe group comprises a water storage barrel, a conveying pump, a seepage pipe, a water outlet pipe, a recycling barrel and weighing equipment, the conveying pump communicates the water storage barrel with one box body through the seepage pipe, and the water outlet pipe communicates the other box body with the recycling barrel. The test simulation of the synergistic effect of three fields of temperature, seepage and stress is realized, the complex environment of moraine soil in cold region engineering is accurately restored, and a reliable test platform is provided for exploring a multi-field coupling mechanism.

Description

Technical Field

[0001] This invention relates to the field of technology, and in particular to a device and method for testing the residual strength of glacial till. Background Technology

[0002] In geotechnical engineering, cold-region engineering, and geological disaster prevention, accurately obtaining the shear strength parameters of glacial till under complex environments is crucial. Repeated direct shear tests are a classic method for determining the residual strength of glacial till, and can be used to understand the strength decay pattern after damage. However, the actual environment in which glacial till exists is complex, and existing technologies, such as the patent application number 201910539349, which directly tests the physical and mechanical parameters of glacial till samples, cannot meet the research needs of cold-region engineering regarding the mechanism of residual strength change in glacial till, nor can they support stability assessments in practical engineering projects. Summary of the Invention

[0003] This invention provides a device and method for testing the residual strength of glacial till, which solves the problem that the existing technology of directly testing the physical and mechanical parameters of glacial till is difficult to support the stability in actual engineering.

[0004] This invention provides a residual strength testing device for glacial till, comprising a sample shearing box, a shearing assembly, a temperature regulating component, and a simulation tube assembly; The sample shearing box includes two boxes stacked one on top of the other, and each box has a placement cavity for accommodating the sample to be tested. The shearing assembly includes a pusher and a shear stress detection device. The pusher is connected to one of the boxes, and the shear stress detection device is connected to the other box. The pusher is used to push the two boxes to move relative to each other on a horizontal plane, and the shear stress detection device is used to detect and collect stress data on the boxes connected to it. The simulated pipe assembly includes a water storage tank, a delivery pump, a seepage pipe, an outlet pipe, a recycling tank, and a weighing device. The delivery pump connects the water storage tank to one of the boxes through the seepage pipe, and the outlet pipe connects another box to the recycling tank. The recycling tank is placed on the weighing device.

[0005] The temperature regulating component is connected to the sample shearing box and is used to regulate the temperature of the sample shearing box.

[0006] Furthermore, the pushing component includes a pushing cylinder and a first air pump, the first air pump being used to drive the pushing cylinder to extend and retract. The shear stress detection device includes a connecting frame, a support frame, an elastic transmission component, and a force gauge. The piston rod end of the pushing cylinder is fixedly connected to one of the housings, the connecting frame is fixedly connected to another housing, the force gauge is fixedly connected to the connecting frame, one end of the elastic transmission component is connected to the force gauge, and the other end of the elastic transmission component is connected to the support frame.

[0007] Furthermore, two seepage pipes and two outlet pipes are provided, each of the two seepage pipes is connected to one of the boxes, and each of the two outlet pipes is connected to one of the boxes. Control valves are connected to the seepage pipes and the outlet pipes respectively.

[0008] Furthermore, it also includes a thermal insulation layer, and the sample shearing box is disposed within the thermal insulation layer.

[0009] Furthermore, a pressure frame is fixedly connected to the box body, the pressure frame is located at the top of the sample shearing box, a clamping cylinder is fixedly connected to the pressure frame, a second air pump is connected to the clamping cylinder, the second air pump is used to drive the clamping cylinder to extend and retract, the piston rod of the clamping cylinder is located on the side close to the box body, and a clamping plate is fixedly connected to the end of the piston rod of the clamping cylinder close to the box body.

[0010] Furthermore, the temperature regulating component includes a water bath, a constant temperature pipeline, and a hot and cold circulation machine. The hot and cold circulation machine is connected to the water bath through the constant temperature pipeline. A heat-conducting medium is provided inside the water bath, and the sample shearing box is connected inside the water bath.

[0011] Furthermore, the bottom of the water bath is covered with multiple ball bearings.

[0012] Furthermore, it also includes an industrial control computer, which is communicatively connected to the pusher, shear stress detection equipment, weighing equipment, and delivery pump.

[0013] Furthermore, it also includes a PIV analyzer, the housing is made of a light-transmitting material, the PIV analyzer is positioned opposite the housing and is used to monitor image information inside the housing through the housing, and the PIV analyzer is communicatively connected to the industrial control computer.

[0014] This invention also provides a method for testing the residual strength of glacial till, applied to a device for testing the residual strength of glacial till, comprising the following steps: S1: Sample preparation and installation. Prepare remolded or undisturbed glacial till samples according to the geotechnical testing specifications and install the samples in the sample shearing box. S2: Activate the temperature regulator to maintain the temperature of the experimental environment; S3: The sample is saturated and consolidated. Water is injected into the sample through the simulated tube assembly until it is saturated, and then the sample is compacted. S4: As required by the test, simulate the seepage state by setting up the simulated pipe group, and conduct ordinary direct shear test or repeated direct shear test on the box by controlling the pusher, and monitor the seepage data during the direct shear test simultaneously; S5: Store test data. After the test requirements are met, stop shearing, save the test data, and record the mass change displayed on the weighing device.

[0015] The beneficial effects of this invention are as follows: 1. The experiment simulates the synergistic effects of temperature, seepage, and stress, accurately reproducing the complex environment of glacial till in cold-region engineering, and providing a reliable experimental platform for exploring the multi-field coupling mechanism.

[0016] 2. The seepage system, through the design of double seepage pipes, double outlet pipes and control valves, can flexibly realize unidirectional seepage in the upper part, unidirectional seepage in the lower part, bidirectional seepage and non-drainage conditions, completely simulating the complex seepage path in actual engineering, and filling the gap in existing research on the impact of complex seepage on the residual strength of glacial till.

[0017] 3. The shear box is made of light-transmitting material, and the PIV analyzer is precisely fixed by the fixture, which effectively solves the monitoring fluctuation problem caused by the reciprocating motion of the shear box during repeated straight shearing, and realizes stable visualization of the entire experimental process. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the connection relationship of the PIV analyzer in an embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of the sample shearing box in an embodiment of the present invention.

[0021] Figure label: 1. Sample shearing box; 111. Upper shearing box; 112. Lower shearing box; 12. Placement cavity; 13. Pressure plate; 14. Ball bearing; 15. Pressure cylinder; 16. Pressure frame; 17. Fixing frame; 2. Push cylinder; 21. First air pump; 22. Second air pump; 23. Air pipe; 31. Hot and cold circulation machine; 32. Insulation layer; 33. Sliding door; 34. Water bath; 35. Constant temperature pipeline; 41. Transfer pump; 42. Water storage tank; 43. Seepage pipe; 44. Control valve; 45. Water outlet pipe; 46. Recycling tank; 47. Weighing equipment; 51. Dial indicator; 52. Data connection cable; 53. Industrial control computer; 54. Multi-channel controller; 55. Force gauge; 56. Spring; 57. Support frame; 58. Connecting frame; 59. Analyzer. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0023] The terms "first" and "second" in the specification and claims of this invention may explicitly or implicitly include one or more of those features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0025] The following is combined with Figures 1-3 This invention describes a residual strength testing device for glacial till, comprising a sample shearing box, a shearing assembly, a temperature regulating component, and a simulated tube assembly. The sample shearing box comprises two stacked boxes, each containing a placement cavity 12 for accommodating the sample to be tested. The shearing assembly includes a pushing component and a shear stress detection device. The pushing component is connected to one box, and the shear stress detection device is connected to the other box. The pushing component is used to move the two boxes relative to each other on a horizontal plane, and the shear stress detection device is used to detect and collect stress data on the connected boxes. The simulated tube assembly includes a water storage tank 42, a delivery pump 41, a seepage pipe 43, an outlet pipe 45, a recovery tank 46, and a weighing device 47. The delivery pump 41 connects the water storage tank 42 to one box via the seepage pipe 43, and the outlet pipe 45 connects the other box to the recovery tank 46, which is placed on the weighing device 47. The temperature regulating component is connected to the sample shearing box and is used to regulate the temperature of the sample shearing box.

[0026] Specifically, such as Figure 1 , Figure 3 As shown, the sample shearing box consists of two stacked boxes, with the upper box designated as the upper shearing box 111 and the lower box designated as the lower shearing box 112. The two boxes are interconnected on opposite sides, forming a common placement cavity 12 for holding the glacial till sample. The boxes are made of transparent fiberglass, meeting both the requirements for visual monitoring and possessing sufficient structural strength to withstand friction and pressure during the shearing process. A pushing component is connected to the lower shearing box 112, and a shear stress detection device is connected to the upper shearing box 111. The pushing component is used to move the upper shearing box 111 and the lower shearing box 112 relative to each other on a horizontal plane, thereby achieving the shearing function. The shear stress detection device is used to detect and collect stress data on the connected boxes.

[0027] The simulation tube assembly is used to simulate the residual strength test of glacial till under seepage conditions. Specifically, a horizontal flow pump is selected as the delivery pump 41. The delivery pump 41 connects the water storage tank 42 to one of the boxes through the seepage pipe 43, and the outlet pipe 45 connects the other box to the recovery tank 46. The delivery pump 41 pumps water from the water storage tank 42 into the box, and after seepage through the sample, it flows out from the outlet pipe 45 to the recovery tank 46. The weighing device 47 is an electronic balance, which weighs the mass of seepage water collected in the recovery tank 46 in real time to facilitate subsequent calculation of permeability. The temperature regulating component is connected to the shear box to regulate the overall temperature of the shear box to meet the temperature environment requirements of the test.

[0028] Furthermore, the pushing component includes a pushing cylinder 2 and a first air pump 21, the first air pump 21 being used to drive the pushing cylinder 2 to extend and retract. The shear stress detection device includes a connecting frame 58, a support frame 57, an elastic transmission component, and a force gauge 55. The piston rod end of the pushing cylinder is fixedly connected to one housing, the connecting frame 58 is fixedly connected to another housing, and the force gauge 55 is fixedly connected to the connecting frame 58. One end of the elastic transmission component is connected to the force gauge 55, and the other end of the elastic transmission component is connected to the support frame 57.

[0029] Specifically, such as Figure 1 As shown, the piston rod end of the pushing cylinder 2 is fixedly connected to the lower shear box 112, the connecting frame 58 is fixedly connected to the upper shear box 111, and the force gauge 55 is fixedly connected to the connecting frame 58. The elastic transmission element is set as a spring 56 to transmit the thrust. One end of the elastic transmission element is connected to the force gauge 55, and the other end is connected to the support frame 57. The support frame 57 is fixedly connected to the table or test bench. When the pushing cylinder 2 pushes the two boxes to move relative to each other, the shear force on the box connected to the connecting frame 58 is transmitted to the force gauge 55 through the connecting frame 58. The support frame 57 is fixed, the elastic transmission element is compressed, thereby applying stress to the force gauge 55. The force gauge 55 converts the stress signal into an electrical signal and transmits it to the data acquisition system to realize the real-time detection and acquisition of shear stress.

[0030] Furthermore, two seepage pipes 43 and two outlet pipes 45 are provided respectively. Each of the two seepage pipes 43 is connected to a box, and each of the two outlet pipes 45 is connected to a box. Control valves 44 are connected to the seepage pipes 43 and the outlet pipes 45 respectively.

[0031] Two seepage pipes 43 and two outlet pipes 45 are provided. One seepage pipe 43 is connected to the upper shear box 111, and the other seepage pipe 43 is connected to the lower shear box 112. One outlet pipe 45 is connected to the upper shear box 111, and the other outlet pipe 45 is connected to the lower shear box 112. Each seepage pipe 43 and each outlet pipe 45 is connected to a control valve 44. By adjusting the on / off state of the control valves 44 on different seepage pipes 43 and outlet pipes 45, various seepage modes such as unidirectional seepage in the upper part, unidirectional seepage in the lower part, or bidirectional seepage can be achieved, accurately simulating complex seepage conditions in actual engineering.

[0032] Furthermore, it also includes an insulation layer 32, and the shear box is disposed within the insulation layer 32.

[0033] Specifically, such as Figure 2 As shown, the insulation layer 32 is made of polyurethane insulation material, with an internal antifreeze and insulation coating. The shear box and part of the seepage pipe 43 are located inside the insulation layer 32. The top of the insulation layer 32 has an openable sliding door 33 for easy installation, adjustment, and maintenance of the internal equipment and pipelines. The insulation layer 32 can effectively reduce the influence of the external ambient temperature on the internal temperature of the shear box during the test, ensuring the stability of temperature control. If the test does not require temperature control, the insulation layer 32 can be completely removed.

[0034] Furthermore, a pressure frame 16 is fixedly connected to the box body. The pressure frame 16 is located at the top of the sample shearing box. A clamping cylinder 15 is fixedly connected to the pressure frame 16. A second air pump 22 is connected to the clamping cylinder 15 through an air pipe 23. The piston rod of the clamping cylinder 15 is located on the side close to the box body. A clamping plate 13 is fixedly connected to the end of the piston rod of the clamping cylinder 15 close to the box body.

[0035] Specifically, such as Figure 1As shown, a pressure frame 16 is fixedly connected to the top of the upper shear box 111. The pressure frame 16 has a portal frame structure and spans across the upper shear box 111. A clamping cylinder 15 is fixedly connected to the middle of the crossbeam of the pressure frame 16. The piston rod of the clamping cylinder 15 is vertically downward and located on the side close to the upper shear box 111. A clamping plate 13 is fixedly connected to the lower end of the piston rod of the clamping cylinder 15. The clamping plate 13 is located inside the upper shear box 111, and its contour matches the internal contour of the upper shear box 111. When the clamping cylinder 15 is activated, the second air pump 22 drives the piston rod of the clamping cylinder 15 to move the clamping plate 13 downward, applying vertical consolidation stress to the glacial till sample inside the shear box to meet the requirements of the sample consolidation test.

[0036] In one specific embodiment, such as Figure 1 As shown, a pressure plate 13 is also provided at the bottom of the placement cavity 12 as a support, and the piston rod of the pressure cylinder 15 is connected to the pressure plate 13 above. The pressure plate 13 is made of permeable stone, and the seepage pipe 43 and the outlet pipe 45 are connected to the placement cavity 12 through the permeable stones on the upper and lower sides, respectively.

[0037] In one specific embodiment, a dial indicator 51 is also installed on the pressure frame 16. The detection head of the dial indicator 51 is in contact with the upper surface of the pressure plate 13 to collect the downward movement distance of the pressure plate 13 in real time, thereby providing feedback on the degree of deformation of the glacial till sample.

[0038] Furthermore, the temperature control components include a water bath 34, a constant temperature pipe 35, and a hot and cold circulation machine 31. The hot and cold circulation machine 31 is connected to the water bath 34 through the constant temperature pipe 35. A heat-conducting medium is provided inside the water bath 34, and the sample shearing box is connected inside the water bath 34.

[0039] Specifically, such as Figure 1 As shown, the thermal cycling machine 31 is connected to the inlet and outlet of the water bath 34 via a constant temperature pipe 35, forming a closed loop. The water bath 34 contains a heat-conducting medium, which is a mixture of antifreeze and water. The bottom of the lower shear box 112 is embedded in the heat-conducting medium of the water bath 34 and is fixedly connected to the bottom of the water bath 34. The temperature of the heat-conducting medium is adjusted by the thermal cycling machine 31, and the heat-conducting medium transfers the temperature to the shear box and the internal sample through heat conduction, achieving precise control of the test environment temperature. The temperature control range can cover the low-temperature environment common in cold-region engineering to the normal temperature environment.

[0040] Furthermore, the bottom of the water bath 34 is covered with multiple ball bearings 14.

[0041] Specifically, such as Figure 1As shown, the lower shear box 112 is fixedly connected to the bottom of the water bath 34, and the piston rod of the pushing cylinder 2 is fixedly connected to the side wall of the lower shear box 112. Multiple ball bearings 14, made of high-strength stainless steel, are evenly distributed on the bottom support surface of the water bath 34. When the pushing cylinder 2 pushes the lower shear box 112 and the water bath 34 to move together, the upper shear box 111 is subjected to a reverse thrust from the connecting frame 58, causing the upper shear box 111 and the lower shear box 112 to move relative to each other. The ball bearings 14 can convert the sliding friction at the bottom of the water bath 34 into rolling friction, significantly reducing the frictional force of the water bath 34 during the movement of the lower shear box 112, avoiding interference from frictional force on the shear stress detection results, and ensuring the accuracy of the test data.

[0042] Furthermore, it also includes an industrial control computer 53, which is communicatively connected to the pusher, the shear stress detection equipment, the weighing equipment 47, and the delivery pump 41.

[0043] In one specific embodiment, such as Figure 1 As shown, the industrial control computer 53 is configured as a computer. Through a multi-channel controller 54 and a data connection cable 52, the industrial control computer 53 communicates with the first air pump 21, force gauge 55, weighing device 47, dial indicator 51, second air pump 22, and delivery pump 41 of the pushing component, thereby controlling the execution of the pushing cylinder 2, delivery pump 41, and clamping cylinder 15, and collecting and storing the data monitored by the force gauge 55, weighing device 47, and dial indicator 51. For the pushing cylinder 2 and vertical clamping cylinder 15 of the pushing component, the industrial control computer 53 controls the operation of the first air pump 21 and the second air pump 22, respectively, to achieve extension and retraction control of the pushing cylinder 2 and clamping cylinder 15.

[0044] In some optional embodiments, the industrial control computer 53 has built-in dedicated control software, which can set the thrust, frequency and stroke of the cylinder 2 through the software interface to realize the automated control of ordinary direct shear test or repeated direct shear test; at the same time, the industrial control computer 53 receives stress data transmitted by the force gauge 55 and seepage water quality data transmitted by the weighing device 47 in real time, and stores, displays and analyzes the data in real time to generate test curves and data reports, thereby improving the automation level of the test and the efficiency of data processing.

[0045] Furthermore, such as Figure 2 As shown, it also includes a PIV analyzer 59. The housing is made of a light-transmitting material. The PIV analyzer 59 is positioned opposite the housing and is used to monitor image information inside the housing through the housing. The PIV analyzer 59 is communicatively connected to the industrial control computer 53.

[0046] Specifically, both the upper shear box 111 and the lower shear box 112 are made of transparent fiberglass to ensure that the light from the PIV analyzer 59 can penetrate the box. The PIV analyzer 59 is fixed to the outside of the shear box by a mounting bracket 17, with its lens facing the placement cavity 12 of the shear box. This lens is used to capture and monitor the internal structural changes of the glacial till sample inside the box during the shearing process in real time, especially the morphological changes of ice in the pores. The PIV analyzer 59 is connected to the industrial control computer 53 to transmit the captured image data. The industrial control computer 53 processes the image data using dedicated image analysis software to achieve visualized monitoring and analysis of the shearing process.

[0047] In some alternative embodiments, the PIV analyzer 59 adopts a modular design and can be disassembled and replaced with other monitoring instruments such as acoustic emission sensors and conductivity sensors according to test requirements. All replaced instruments are treated with antifreeze to adapt to low-temperature test environments.

[0048] This invention also discloses a method for testing the residual strength of glacial till, comprising the following steps: S1: Sample preparation and installation. Prepare remolded or undisturbed glacial till samples according to geotechnical testing specifications and install the samples in the sample shearing box.

[0049] Specifically, according to geotechnical testing specifications, suitable glacial till raw materials are selected to prepare remolded or undisturbed glacial till samples. The ice content of the samples is strictly controlled to ensure that the sample performance meets the test design requirements. The prepared samples are then placed smoothly into the placement cavity 12 of the sample shearing box, ensuring that the samples fit tightly against the inner wall of the sample shearing box without any looseness or gaps. Subsequently, the relevant pipelines and lines of the simulation tube assembly, shearing component, and clamping cylinder 15 are connected, and all connections are checked to ensure good sealing and no leakage or poor contact, in preparation for subsequent tests.

[0050] S2: Activate the temperature regulator to ensure the temperature of the experimental environment.

[0051] Specifically, the hot and cold circulation machine 31 is started, and the equipment parameters are adjusted according to the temperature requirements set for the experiment. The constant temperature pipe 35, in conjunction with the water bath 34, stabilizes the temperature of the shear box and the internal sample at the target value, which can be set to -20 to 0℃. During temperature adjustment, the insulation layer 32 wrapped around the outside of the shear box reduces the influence of the external environment on the temperature, preventing the ice in the moraine from melting due to temperature fluctuations, ensuring a constant experimental temperature and providing stable temperature conditions for the experiment. Simultaneously, the data monitoring and acquisition devices are started, including a dial gauge 51, a force gauge 55, a PIV analyzer 59, an industrial computer 53, and a multi-channel controller 54. The data connection cable 52 is checked for reliability to ensure the normal operation of each monitoring device. The dial gauge 51 is fixed above the shear box and keeps in contact with the upper shear box 111 to prepare for monitoring the sample deformation during consolidation. The PIV analyzer 59, through the mounting bracket 17, is directly facing the shear box to complete the debugging of visual monitoring, ensuring real-time and accurate data acquisition during the experiment.

[0052] S3: Sample saturation and consolidation. Water is injected into the sample through a simulated tube assembly until saturation, and then the sample is compacted.

[0053] The delivery pump 41 of the seepage system is started, and liquid is injected into the shear box through the seepage pipe 43 to saturate the sample. After the sample is fully saturated, a predetermined vertical stress is applied to the sample by controlling the clamping cylinder 15 to perform a consolidation operation. During the process, the deformation of the sample is monitored in real time by a dial gauge 51 until the deformation reaches the stable state required by the specification, avoiding subsequent shear tests when the deformation is unstable and ensuring the accuracy of the test.

[0054] S4: As required by the test, simulate the seepage state by simulating the pipe group, and conduct ordinary direct shear test or repeated direct shear test on the box by controlling the pusher, and monitor the seepage data during the direct shear test simultaneously.

[0055] Specifically, the temperature path, seepage conditions, and shear plan required for the test are set via the industrial control computer 53. The seepage conditions can be achieved by adjusting the control valve 44 on the seepage pipe 43 and the outlet pipe 45. Depending on the test requirements, the upper unidirectional seepage, lower unidirectional seepage, bidirectional seepage, or no-drainage condition can be selected. At the same time, the shear mode is set via the industrial control computer 53. Depending on the test requirements, a normal direct shear test or a repeated direct shear test can be selected, and the corresponding shear parameters can be determined.

[0056] The shearing program is initiated, and the lower shear box 112 is pushed relative to the upper shear box 111 by the pusher to achieve the shearing action on the sample. During the shearing process, the force gauge 55 detects and collects shear stress data in real time and transmits it to the industrial control computer 53 through the data connection line 52; the PIV analyzer 59 monitors the changes in the internal structure of the sample in real time through the transparent shear box, especially the morphological changes of ice in the pores, and transmits the image information to the industrial control computer 53; the weighing device 47 monitors the mass of seepage water in the recovery tank 46 in real time and records the seepage data, realizing comprehensive synchronous monitoring of the coupling process of shearing, temperature and seepage.

[0057] S5: Store test data. After the test requirements are met, stop shearing, save the test data, and record the mass change displayed on the weighing device.

[0058] When the shear test reaches the set requirements (such as the predetermined number of shearings, shear displacement, etc.), the shearing is stopped by controlling the pusher to stop. All test data, including stress data, deformation data, seepage flow data, and image data, are saved by the industrial control computer 53; at the same time, the mass change of the seepage water in the recovery tank 46 displayed by the electronic balance is accurately recorded, providing complete data support for subsequent test analysis.

[0059] Specifically, it also includes step S6, the test completion process: shutting down all test instruments, including temperature regulators, delivery pump 41, first air pump 21, second air pump 22, data monitoring and acquisition devices, etc. The seepage water in the recovery tank 46 is recycled to reduce water waste and complete the entire test process.

[0060] Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for testing the residual strength of glacial till, characterized in that: Includes a sample shearing box, shearing assembly, temperature control components, and simulation tube assembly; The sample shearing box includes two boxes stacked one on top of the other, and each box has a placement cavity for placing the sample to be tested. The shearing assembly includes a pusher and a shear stress detection device. The pusher is connected to one of the boxes, and the shear stress detection device is connected to the other box. The pusher is used to push the two boxes to move relative to each other on a horizontal plane, and the shear stress detection device is used to detect and collect stress data on the boxes connected to it. The simulated pipe assembly includes a water storage tank, a delivery pump, a seepage pipe, an outlet pipe, a recycling tank, and a weighing device. The delivery pump connects the water storage tank to one of the boxes through the seepage pipe, and the outlet pipe connects another box to the recycling tank. The recycling tank is placed on the weighing device. The temperature regulating component is connected to the sample shearing box and is used to regulate the temperature of the sample shearing box.

2. The residual strength testing device for glacial till soil according to claim 1, characterized in that: The pushing component includes a pushing cylinder and a first air pump. The first air pump is used to drive the pushing cylinder to extend and retract. The shear stress detection device includes a connecting frame, a support frame, an elastic conductor, and a force gauge. The piston rod end of the pushing cylinder is fixedly connected to one of the housings. The connecting frame is fixedly connected to another housing. The force gauge is fixedly connected to the connecting frame. One end of the elastic conductor is connected to the force gauge, and the other end of the elastic conductor is connected to the support frame.

3. The residual strength testing device for glacial till soil according to claim 1, characterized in that: Two seepage pipes and two outlet pipes are provided, each of the two seepage pipes is connected to one of the boxes, and each of the two outlet pipes is connected to one of the boxes. Control valves are connected to the seepage pipes and the outlet pipes respectively.

4. The residual strength testing device for glacial till soil according to claim 1, characterized in that: It also includes a thermal insulation layer, and the sample shearing box is disposed within the thermal insulation layer.

5. The residual strength testing device for glacial till soil according to claim 1, characterized in that: A pressure frame is fixedly connected to the box body. The pressure frame is located at the top of the sample shearing box. A clamping cylinder is fixedly connected to the pressure frame. A second air pump is connected to the clamping cylinder. The second air pump is used to drive the clamping cylinder to extend and retract. The piston rod of the clamping cylinder is located on the side close to the box body. A clamping plate is fixedly connected to the end of the piston rod of the clamping cylinder close to the box body.

6. The residual strength testing device for glacial till soil according to claim 5, characterized in that: The temperature regulating component includes a water bath, a constant temperature pipeline, and a hot and cold circulation machine. The hot and cold circulation machine is connected to the water bath through the constant temperature pipeline. The water bath contains a heat-conducting medium, and the sample shearing box is connected inside the water bath.

7. The residual strength testing device for glacial till soil according to claim 6, characterized in that: The bottom of the water bath is covered with multiple ball bearings.

8. The residual strength testing device for glacial till soil according to claim 1, characterized in that: It also includes an industrial control computer, which is communicatively connected to the pusher, shear stress detection equipment, weighing equipment and delivery pump.

9. The residual strength testing device for glacial till soil according to claim 8, characterized in that: It also includes a PIV analyzer. The housing is made of a light-transmitting material. The PIV analyzer is positioned opposite to the housing and is used to monitor image information inside the housing through the housing. The PIV analyzer is communicatively connected to the industrial control computer.

10. A method for testing the residual strength of glacial till, applied to the glacial till residual strength testing device according to any one of claims 1-9, characterized in that, Includes the following steps: S1: Sample preparation and installation. Prepare remolded or undisturbed glacial till samples according to the geotechnical testing specifications and install the samples in the sample shearing box. S2: Activate the temperature regulator to maintain the temperature of the experimental environment; S3: The sample is saturated and consolidated. Water is injected into the sample through the simulated tube assembly until it is saturated, and then the sample is compacted. S4: As required by the test, simulate the seepage state by setting up the simulated pipe group, and conduct ordinary direct shear test or repeated direct shear test on the box by controlling the pusher, and monitor the seepage data during the direct shear test simultaneously; S5: Store test data. After the test requirements are met, stop shearing, save the test data, and record the mass change displayed on the weighing device.

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