A large-scale stress-type shear test device and a use method thereof

Abstract

The application provides a large-scale stress type shearing test device and a use method, which comprises a bottom plate, a shearing lower box and a shearing upper box, the top of the bottom plate is respectively provided with a first horizontal counterforce frame and a second horizontal counterforce frame on both sides, and the height of the first horizontal counterforce frame is higher than that of the second horizontal counterforce frame. The scheme adopts a large-scale direct shear instrument structure, has large size and weak hoop effect, and can truly simulate the interaction between piles and soil in actual engineering. Meanwhile, through the anti-overturning guide structure of a convex rail and a connecting groove, a vertical drainage channel formed by an upper box drainage hole and a lower box drainage groove net, a linear guide rail sliding block mechanism with a friction coefficient of less than or equal to 0.05, and adaptive loading control and double force ring redundancy verification based on PLC, the stability, drainage efficiency, loading accuracy and safety of the test are significantly improved, and the limit shear force under different interface conditions can be accurately measured, thereby providing a reliable basis for the research on the bearing capacity of pile foundations.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering testing equipment technology, specifically to a large-scale stress-type shear testing device and its usage method. Background Technology

[0002] Defects such as diameter enlargement, diameter reduction, and mud cake often occur during the construction of bored piles. The impact of these factors on the bearing capacity of pile foundations lacks mature theoretical guidance. The mechanical properties of the pile-soil interface are the foundation of pile foundation bearing capacity theory.

[0003] Currently, conventional direct shear testers are small in size, have a significant upper box hoop effect, and require the lower box structure to have a flat and uniform surface. They cannot simulate complex interface conditions such as roughness, convexity, concaveness, or mud skin on the pile body surface, resulting in low test accuracy.

[0004] While existing large direct shear apparatuses can reduce the hoop effect, they still have problems such as the upper and lower boxes being prone to tipping over, imperfect drainage systems, limited loading control methods, and difficulty in accurately measuring ultimate shear force. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a large-scale stress-type shear testing device and its usage method, solving the problems mentioned in the background art, such as the upper and lower boxes being prone to relative overturning during the shearing process, imperfect drainage systems, single loading control methods, and difficulty in accurately measuring the ultimate shear force under complex interface conditions.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a large-scale stress-type shear test device and its usage method, comprising a base plate, a lower shear box, and an upper shear box. A first horizontal reaction frame and a second horizontal reaction frame are respectively provided on the top two sides of the base plate. The height of the first horizontal reaction frame is higher than that of the second horizontal reaction frame. The lower shear box and the upper shear box are located between the first and second horizontal reaction frames. Connecting grooves are provided on both sides of the bottom of the upper shear box. Convex rails are fixedly provided on both sides of the top of the lower shear box, and the convex rails slide in conjunction with the connecting grooves. Four drainage holes are provided on both sides of the upper shear box. A drainage trough mesh is provided at the bottom of the lower shear box, and a drainage outlet is provided on one side of the lower shear box.

[0007] Preferably, a linear guide rail is installed on the top of the base plate and below the shearing box, and the linear guide rail is bolted to the base plate.

[0008] Preferably, the bottom of the shearing box is provided with two arc-shaped sliders on both sides, the sliders on both sides are symmetrically arranged, the sliders are slidably connected to the linear guide rail, and a displacement measuring device is provided on one side of the linear guide rail.

[0009] Preferably, a vertical reaction frame is installed on the upper end of the shearing box, a vertical pressurizing device is fixedly installed inside the vertical reaction frame, a jack rod is provided at the bottom of the vertical pressurizing device, a vertical pressing head is fixedly installed at the bottom of the jack rod, and a second force ring is installed on one side of the vertical pressing head.

[0010] Preferably, a support steel is installed at one end of the first horizontal reaction frame near the upper shear box, and an upper box connecting gasket is installed on the top of the support steel. The upper box connecting gasket is installed and connected to one side of the outer end face of the upper shear box.

[0011] Preferably, a second support steel is installed on the side of the second horizontal reaction frame near the shear box, a horizontal connecting plate is installed on one end of the second support steel, a horizontal loading device is fixedly installed on one end of the horizontal connecting plate, and the top of the horizontal loading device is installed and connected to one side of the shear box.

[0012] Preferably, a first load-measuring ring is installed on one side of the horizontal loading device, and a third load-measuring ring is installed on one side of the supporting steel.

[0013] This invention provides a large-scale stress-type shear testing device and its usage method. It has the following beneficial effects: This scheme employs a large-scale direct shear apparatus structure, characterized by its large size and weak clamping effect, enabling realistic simulation of pile-soil interaction in actual engineering projects. Simultaneously, through an anti-overturning guide structure with convex rails and connecting grooves, a vertical drainage channel formed by drainage holes in the upper box and drainage channels in the lower box, a linear guide rail slider mechanism with a friction coefficient ≤0.05, and PLC-based adaptive loading control and dual-force-loop redundancy verification, the stability, drainage efficiency, loading accuracy, and safety of the experiment are significantly improved. It can accurately determine the ultimate shear force under different interface conditions, providing a reliable basis for pile foundation bearing capacity research. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the external structure of the present invention; Figure 2 This is a front view structural diagram of the present invention; Figure 3 For the present invention Figure 2 A cross-sectional view along the AA direction; Figure 4 This is a flowchart of the method of the present invention.

[0015] In the diagram: 101, base plate; 102, first horizontal reaction frame; 103, supporting steel; 104, vertical reaction frame; 105, vertical pressurizing equipment; 106, second force ring; 107, vertical downward pressure head; 109, first force ring; 110, horizontal loading equipment; 111, second horizontal reaction frame; 112, second supporting steel; 113, drainage hole; 114, linear guide rail; 115, drainage trough; 116, lower shear box; 117, drainage outlet; 118, upper shear box; 119, jack pressure rod; 120, horizontal connecting plate; 121, convex rail; 122, connecting groove; 123, slider; 124, upper box connecting gasket; 125, third force ring. Detailed Implementation

[0016] This invention provides a large-scale stress-type shear testing device and its usage method, such as... Figure 1-3 As shown, the device includes a base plate 101, a lower shear box 116, and an upper shear box 118. A first horizontal reaction frame 102 and a second horizontal reaction frame 111 are respectively provided on the top two sides of the base plate 101. The first horizontal reaction frame 102 is higher than the second horizontal reaction frame 111. The lower shear box 116 and the upper shear box 118 are located between the first horizontal reaction frame 102 and the second horizontal reaction frame 111. Connecting grooves 122 are provided on both sides of the bottom of the upper shear box 118. A convex rail 121 is fixedly provided on both sides of the top of the lower shear box 116, and the convex rail 121 slides in conjunction with the connecting groove 122. Four drainage holes 113 are opened on both sides of the upper shear box 118. A drainage mesh 115 is provided at the bottom of the lower shear box 116, and a drainage outlet 117 is opened on one side of the lower shear box 116.

[0017] It is worth further explaining that the fit gap between the convex rail 121 and the connecting groove 122 is controlled within 0.5mm. The two form an anti-tipping guide structure, which can effectively suppress the lateral tilting of the upper shear box 118 relative to the lower shear box 116 during the shearing process, and ensure that the shearing surface always remains horizontal.

[0018] It should be further explained that the drainage holes 113 are symmetrically distributed on both sides of the shear box 118 along the shear direction, 10mm away from the top of the box. The drainage trough mesh 115 is a crisscrossing groove structure with a groove width of 3mm and a depth of 2mm. The distance between adjacent grooves is ≤10mm. The drainage holes 113, drainage trough mesh 115 and drainage outlet 117 are connected in sequence to form a vertical drainage channel, which is suitable for drainage consolidation tests of saturated soil.

[0019] Furthermore, a linear guide rail 114 is installed on the top of the base plate 101 and below the shearing box 116, and the linear guide rail 114 is bolted to the base plate 101.

[0020] It is worth further explaining that the linear guide rail 114 is provided with mechanical limit blocks and hydraulic buffers at both ends, which are used to limit the maximum horizontal stroke of the shear box 116 and absorb impact energy, prevent overtravel and derailment, and improve equipment safety.

[0021] Furthermore, the bottom of the shearing box 116 is provided with two arc-shaped sliders 123 on both sides. The sliders 123 on both sides are symmetrically arranged. The sliders 123 are slidably connected to the linear guide rail 114. A displacement measuring device is provided on one side of the linear guide rail 114.

[0022] It should be further explained that the slider 123 and the linear guide rail 114 have rolling or sliding friction with a friction coefficient ≤0.05, which ensures that the shear box 116 moves smoothly and without crawling during horizontal loading, which is beneficial for accurately measuring the interface shear stress.

[0023] It is worth further explaining that the displacement measurement device includes a normal displacement sensor and a horizontal displacement sensor. The normal displacement sensor is installed between the crossbeam of the vertical reaction frame 104 and the top of the shear upper box 118, and is used to monitor the amount of compression deformation of the soil sample under normal stress in real time. A horizontal displacement sensor is installed between the base plate 101 and the side of the shearing box 116. Specifically, the sensor body is fixed on the base plate 101, and the probe abuts against the side of the shearing box 116 to monitor the horizontal displacement of the shearing box 116 in real time during the shearing process.

[0024] Furthermore, a vertical reaction frame 104 is installed on the upper end of the shearing box 118. A vertical pressurizing device 105 is fixedly installed inside the vertical reaction frame 104. A jack rod 119 is provided at the bottom of the vertical pressurizing device 105. A vertical downward pressing head 107 is fixedly installed at the bottom of the jack rod 119. A second force ring 106 is installed on one side of the vertical downward pressing head 107.

[0025] It is worth further explaining that: a ball joint support is provided between the vertical pressure head 107 and the shear upper box 118, which can automatically center and ensure that the normal stress is evenly distributed on the soil sample surface, avoiding eccentric loading; the second force ring 106 is used to monitor the normal load in real time, with a range of 60kN, and has a built-in electromechanical dial gauge, which is calibrated by a pressure machine before use.

[0026] Furthermore, a support steel 103 is installed on one end of the first horizontal reaction frame 102 near the shear upper box 118, and an upper box connecting gasket 124 is installed on the top of the support steel 103. The upper box connecting gasket 124 is installed and connected to one side of the outer end face of the shear upper box 118.

[0027] It should be further explained that the upper box connecting gasket 124 and the shearing upper box 118 are in flexible contact or hinged, allowing the shearing upper box 118 to have slight free displacement in the horizontal direction, avoiding additional constraints caused by the deformation of the horizontal reaction frame.

[0028] Furthermore, a second support steel 112 is installed on the side of the second horizontal reaction frame 111 near the shear box 116. A horizontal connecting plate 120 is installed on one end of the second support steel 112, and a horizontal loading device 110 is fixedly installed on one end of the horizontal connecting plate 120. The top of the horizontal loading device 110 is installed and connected to one side of the shear box 116.

[0029] Furthermore, a first force-measuring ring 109 is installed on one side of the horizontal loading device 110, and a third force-measuring ring 125 is installed on one side of the supporting steel 103.

[0030] It is worth further explaining that the horizontal loading device 110 is a separate hydraulic jack with a hydraulic sensor connected in parallel. Its range is 0-80MPa and its accuracy is 0.1MPa. The first force ring 109 and the hydraulic sensor form a redundant control loop, which can still control the load amount when there is a power failure or sensor failure. The third force measuring ring 125 is connected to the support steel 103 at one end and to the shear lower box 116 at the other end. It directly measures the horizontal shear force at the interface and verifies the value with the measurement value of the first force measuring ring 109. When the deviation between the two exceeds 5%, the system automatically alarms and suspends the test to ensure data reliability.

[0031] It should be further explained that the device also includes a control system, which is a PLC programmable controller or an industrial computer. Its input module is electrically connected to the second force ring 106, the first force ring 109, the third force ring 125, the hydraulic sensor, the normal displacement sensor, and the horizontal displacement sensor, respectively, for real-time acquisition of normal load, horizontal load, interface shear force, normal displacement, and horizontal displacement data. The output module of the control system is electrically connected to the oil pump solenoid valve of the vertical pressurizing device 105 and the oil pump solenoid valve of the horizontal loading device 110, respectively, for automatic control of loading, unloading and load holding.

[0032] like Figure 4 As shown, a large-scale stress-type shear testing device and its usage method are described below. The specific usage steps are as follows: S100, Install concrete test blocks; The precast concrete test block is placed in the lower shear box 116. Its surface can be made into a flat surface, a convex surface, a concave surface, or treated with mud according to the test requirements. The lower shear box 116 is moved to the working position, and the upper shear box 118 is placed above the lower shear box 116 so that the convex rail 121 and the connecting groove 122 are aligned and slidably engaged. The upper shear box 118 and the lower shear box 116 are temporarily fixed with pins to prevent relative movement.

[0033] S200, backfill; Calculate the required dry soil weight and water volume according to the design moisture content and void ratio, mix thoroughly in a mixer, and fill the mixed soil sample into the shear box 118 in layers. Gently compact each layer to the specified height to ensure that the soil sample is uniform and dense.

[0034] S300, install loading and measurement equipment and connect it to the control system; S301. Install loading equipment: Erect the vertical reaction frame 104 above the shear upper box 118, install the vertical pressurizing device 105, the second force ring 106 and the vertical downward pressure head 107, and ensure that the ball joint support is aligned; connect the horizontal loading device 110 to the side of the shear lower box 116 through the horizontal connecting plate 120, and install the first force ring 109, the third force ring 125 and the hydraulic sensor. S302. Install the measuring equipment: Install the normal displacement sensor between the crossbeam of the vertical reaction frame 104 and the top of the upper shear box 118; install the horizontal displacement sensor between the base plate 101 and the side of the lower shear box 116, with the sensor body fixed to the base plate 101 and the probe abutting against the side of the lower shear box 116. S303, Connect to the control system: Connect the signal lines of the second force ring 106, the first force ring 109, the third force ring 125, the hydraulic sensor, the normal displacement sensor, and the horizontal displacement sensor to the input module of the control system respectively. Connect the oil pump solenoid valve control lines of the vertical pressurizing device 105 and the horizontal loading device 110 to the output module of the control system respectively; The control system is a PLC programmable controller, which is used to receive signals from various sensors, perform PID calculations, and output loading instructions.

[0035] S400, inspection and debugging; Check that all bolt connections are secure and that all sensors and jacks are functioning properly. Turn on the power and check that the dial indicator, strain gauge, and control system are working correctly. Once everything is confirmed to be in order, reset the initial readings to zero.

[0036] S500, apply normal stress and consolidate; Start the vertical pressurization device 105 and apply normal stress to a predetermined value, such as 100kPa, 200kPa, 400kPa, or 600kPa, through the jack rod 119 and the vertical downward pressure head 107. Open the drainage channel to connect the drainage hole 113, the drainage trough mesh 115, and the drainage outlet 117. Collect the normal displacement every 2 minutes. When the difference between two consecutive readings is less than 0.05mm, it is determined that the consolidation has reached stability. If the jack is found to be unloaded during the consolidation process, pressure should be added in time to maintain a constant normal stress.

[0037] S600, pull out the pin, prepare to cut; After consolidation is complete, remove the pins that secure the upper shear box 118 and the lower shear box 116.

[0038] S700, apply horizontal load and adaptively load; The horizontal loading device 110 is activated, and the control system automatically sets the initial load increment based on the estimated interface ultimate shear force. In the initial elastic stage of shear, a large load increment is used, which is 8%-12% of the estimated ultimate shear force; The control system monitors the slope change of the shear force-displacement curve in real time. When it detects that the slope of the curve drops by more than 30% of the initial slope, it automatically determines that it has entered the yield stage and immediately switches to a small load increment, which is 1% to 3% of the estimated ultimate shear force.

[0039] After each level of horizontal load is applied, the control system automatically maintains a constant load and collects the horizontal displacement every 2 minutes. When the difference between two consecutive horizontal displacement readings is less than 0.05 mm, the deformation is determined to be stable, and the next level of load is automatically applied.

[0040] S800, redundancy check and security protection; During the test, the control system collects the shear force values ​​of the first force measuring ring 109 and the third force measuring ring 125 in real time. If the deviation between the two exceeds 5%, the system automatically issues an audible and visual alarm and suspends loading. The operator then checks and decides whether to continue. At the same time, the mechanical limit blocks and hydraulic buffers at both ends of the linear guide rail 114 prevent the shear lower box 116 from overtraveling and derailing.

[0041] S900, terminate the test; The system will automatically stop loading if any of the following conditions occur: Horizontal displacement exceeds 20mm; Under three consecutive load levels, the shear force increment is less than 5% of the shear force of the previous load level; The operator must manually stop it.

[0042] S1000, Data Processing; Save all data collected by the sensors, plot shear stress and horizontal displacement curves, determine parameters such as ultimate shear force, residual strength, and initial shear stiffness of the interface, and analyze the influence of different interface conditions on the mechanical properties of the pile-soil interface through comparison of multiple sets of tests.

[0043] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A large-scale stress-type shear testing device, characterized in that, include: The base plate (101), the lower shear box (116), and the upper shear box (118) are provided with a first horizontal reaction frame (102) and a second horizontal reaction frame (111) on the top two sides of the base plate (101). The first horizontal reaction frame (102) is higher than the second horizontal reaction frame (111). The lower shear box (116) and the upper shear box (118) are located between the first horizontal reaction frame (102) and the second horizontal reaction frame (111). The upper shear box (118) has connecting grooves (122) on both sides of its bottom, and the lower shear box (116) has protruding rails (121) fixed on both sides of its top, with the protruding rails (121) slidingly engaging with the connecting grooves (122). The upper shear box (118) has drainage holes (113) on both sides, the lower shear box (116) has a drainage trough mesh (115) at the bottom, and the lower shear box (116) has a drainage outlet (117) on one side. A linear guide rail (114) is installed on the top of the base plate (101) and below the shearing box (116). Sliders (123) are provided on both sides of the bottom of the shearing box (116), and the sliders (123) are slidably connected to the linear guide rail (114). A vertical reaction frame (104) is mounted on the upper end of the shearing box (118). A vertical pressurizing device (105) is fixed inside the vertical reaction frame (104). A jack rod (119) is provided at the bottom of the vertical pressurizing device (105). A vertical downward pressing head (107) is fixed at the bottom of the jack rod (119). A second force ring (106) is installed on one side of the vertical downward pressing head (107). The first horizontal reaction frame (102) is equipped with a support steel (103) near the end of the shear box (118). The top of the support steel (103) is equipped with an upper box connecting gasket (124), and the upper box connecting gasket (124) is connected to one side of the outer end face of the shear box (118).

2. The large-scale stress-type shear testing device according to claim 1, characterized in that: The second horizontal reaction frame (111) is equipped with a second support steel (112) on the side near the shear box (116). A horizontal connecting plate (120) is installed at one end of the second support steel (112). A horizontal loading device (110) is fixedly provided at one end of the horizontal connecting plate (120). The horizontal loading device (110) is installed and connected to one side of the shear box (116). A first force ring (109) is installed on one side of the horizontal loading device (110), and a third force ring (125) is installed on one side of the support steel (103).

3. The large-scale stress-type shear testing device according to claim 1, characterized in that: A displacement measuring device is provided on one side of the linear guide rail 114. The displacement measuring device includes a normal displacement sensor and a horizontal displacement sensor. The normal displacement sensor is installed between the crossbeam of the vertical reaction frame (104) and the top of the shear upper box (118). The horizontal displacement sensor is installed between the bottom plate (101) and the side of the shear lower box (116).

4. A large-scale stress-type shear testing device according to claim 1, characterized in that: The four drainage holes (113) are symmetrically distributed on both sides of the shear box (118) along the shear direction; The drainage trough mesh (115) has a crisscrossing groove structure; The drainage hole (113), drainage trough (115) and drainage outlet (117) are connected in sequence to form a vertical drainage channel.

5. A large-scale stress-type shear testing device according to claim 1, characterized in that: The linear guide (114) is provided with mechanical limit blocks and hydraulic buffers at both ends.

6. The large-scale stress-type shear testing device according to claim 1, characterized in that: The coefficient of friction between the slider (123) and the linear guide (114) is ≤0.05; The sliders (123) are two in number, which are arranged in an arc shape on both sides of the bottom of the shearing box (116) and are symmetrical in position.

7. A large-scale stress-type shear testing device according to claim 1, characterized in that: A ball joint support is provided between the vertical pressing head (107) and the shearing upper box (118); The second force ring (106) has a range of 60kN and a built-in electromechanical dial indicator.

8. A large-scale stress-type shear testing device according to claim 1, characterized in that: The horizontal loading device (110) is a separate hydraulic jack with a hydraulic sensor connected in parallel; The first force ring (109) and the hydraulic sensor form a redundant control loop; one end of the third force ring (125) is connected to the support steel (103), and the other end is connected to the shearing box (116).

9. A large-scale stress-type shear test method based on the apparatus according to any one of claims 1-8, characterized in that, Includes the following steps: S100. Place the precast concrete test block into the shear box (116) so that the bottom surface of the test block contacts the upper surface of the drainage trough mesh (115) and the sides of the test block are in contact with the inner wall of the shear box (116). Place the upper shear box (118) above the lower shear box (116), insert the convex rail (121) into the connecting groove (122) and slide it until the upper and lower boxes are aligned; Insert pins into the corresponding pin holes on the side walls of the upper shear box (118) and the lower shear box (116) to prevent relative movement between the two during the backfilling and consolidation stages. S200. Prepare soil samples according to the designed moisture content and void ratio, mix them evenly, and fill them into the shear box (118) in layers. Use a compaction rod to gently compact each layer to the specified height so that the soil sample can naturally contact the upper surface of the concrete test block and avoid leaving gaps. The surface of the top layer of soil sample is scraped flat to ensure that the contact surface with the vertical pressing head (107) is flat; S300, Install loading and measuring equipment: Set up the vertical reaction frame (104) above the shear box (118), install the vertical pressurizing device (105), the second force ring (106) and the vertical downward press head (107), and ensure that the ball joint support is aligned; The horizontal loading device (110) is connected to the side of the shear box (116) via the horizontal connecting plate (120), and the first force ring (109), the third force ring (125) and the hydraulic sensor are installed. The normal displacement sensor is installed between the crossbeam of the vertical reaction frame (104) and the top of the shear upper box (118), and the horizontal displacement sensor is installed between the bottom plate (101) and the side of the shear lower box (116). Connect all the above sensor signal lines and jack control lines to the control system, which is a PLC programmable controller with analog input module and digital output module. S400. Check that all bolt connections are secure and that all sensors and jacks are functioning properly. Turn on the control system power and check that all sensor signals are normal and that the jacks move flexibly. Zero all sensor readings and record the initial normal and horizontal displacement zero-point values. S500, Start the vertical pressurization device (105) and apply normal stress to a predetermined value, such as 100kPa, 200kPa, 400kPa or 600kPa, through the jack rod (119) and the vertical pressure head (107); Open the valve of the drain outlet (117) to connect the drain hole (113), the drain trough mesh (115) with the drain outlet (117); Normal displacement is collected every 2 minutes. When the difference between two consecutive readings is less than 0.05 mm, the consolidation is considered to be stable. If the control system detects that the normal load drops by more than 2% of the set value during the consolidation process, it will automatically start the vertical pressurization device (105) to replenish the pressure and keep the normal stress constant. S600, pull out the pins that fix the upper shear box (118) and the lower shear box (116), and manually push the lower shear box (116) gently to confirm that it can slide freely on the linear guide rail (114) without jamming; S700: When a horizontal load is applied, the control system automatically sets the load increment based on the estimated interface ultimate shear force: 8%-12% of the estimated ultimate shear force is used in the elastic stage; when the slope of the shear force-displacement curve drops by more than 30% of the initial slope, it automatically switches to 1%-3% of the estimated ultimate shear force; after each load level, it remains constant, and the next load level is automatically applied when the difference between two consecutive horizontal displacement readings is less than 0.05mm. S800: During the test, the shear force values ​​of the first force ring (109) and the third force ring (125) are collected in real time. If the deviation between the two exceeds 5%, an alarm will be automatically triggered and loading will be suspended. S900. The test shall be terminated when the horizontal displacement exceeds 20mm, or the shear force increment under three consecutive load levels is less than 5% of the previous level, or when the test is manually stopped. S1000 After the test, the control system automatically saves all sensor data, including the normal displacement, horizontal displacement, and shear force values ​​of the first and third load rings for each load level. Divide the shear force value by the bottom area of ​​the shear box (118) to obtain the shear stress, and plot the shear stress versus horizontal displacement curve with horizontal displacement as the abscissa and shear stress as the ordinate. Based on the curves, the peak shear force, residual shear force, initial shear stiffness, and other parameters of the interface are determined, and the influence of different concrete specimen surface morphologies on the mechanical properties of the pile and soil interface is analyzed.

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