A reinforcement-soil interface friction characteristic test device and test method

Abstract

The present invention discloses a reinforcement-soil interface friction characteristic test device and test method, the device comprises a fiber-soil model box, a portable fiber fixing device, a test platform body, a water drop loading device, a traction pulley device, a horizontal observation device, a test platform leveling device, a vertical loading device, a laser displacement sensor and a computer. The present invention obtains the shear stress-strain relationship between the fiber and soil interface under different loads by adjusting the size of the overlying load, thereby obtaining the test parameters such as the shear strength, interface cohesion, internal friction angle, shear displacement, etc. of the interface, and can realize the study of the effect and mechanism of the influence of parameters such as different soil qualities and different fiber types on the test by changing the soil type, soil properties, fiber type, etc., especially for the test study of the friction characteristics of the reinforcement-soil interface of fiber-reinforced soil, revealing the laws of stress and deformation of the reinforcement-soil interface.

Description

Technical Field

[0001] The invention relates to the technical field of reinforcement material property testing, and in particular to a reinforcement-soil interface friction property testing device and a testing method. Background Art

[0002] In reinforced soil engineering, the interface characteristics between the reinforcement material and the soil are a key technical indicator, which will directly affect the stability of the entire reinforced soil engineering. At present, there is no mature and standardized test device and test method for studying the friction characteristics of the fiber reinforced soil bar-soil interface. Therefore, the relevant technologies and data designed in this invention do not involve reference to standard parameters.

[0003] The existing similar device (publication number: CN113484166B, title: A test device for testing shear performance of the interface between fiber and medium, which is the prior application of the applicant) has the following shortcomings:

[0004] (1) At present, vertical loads are applied by stacking, which limits the size of the vertical loads. In addition, the stacking method can easily generate eccentric pressure, which causes the soil in the fiber soil model box to be subjected to eccentric loads.

[0005] (2) Since the mechanical properties of the reinforcement-soil interface are relatively weak, the cohesion and friction between the reinforcement material and the soil are very small, resulting in a very small horizontal traction force that can pull the fiber out of the soil. The horizontal traction force provided by current indoor test equipment is unmeasurable, making data processing difficult.

[0006] (3) Existing instruments are not capable of measuring the horizontal and vertical distribution of multiple fibers, and are not capable of studying the impact of multiple groups of fibers.

[0007] (4) Whether the test bench is level directly affects the accuracy of the test results. Existing instruments cannot achieve leveling of the test bench, which affects the accuracy of the test. Summary of the invention

[0008] In view of the above technical problems, the present invention provides a reinforcement-soil interface friction characteristics test device and test method. By adjusting the size of the overlying load, the shear stress-strain relationship between the fiber and soil interface under different loads is obtained, thereby obtaining test parameters such as the interface shear strength, interface cohesion, internal friction angle, shear displacement, etc. The influence of parameters such as different soil qualities and different fiber types on the test and the influence of the mechanism can be studied by changing the soil type, soil properties, fiber type, etc.

[0009] In order to achieve the above object, the present invention provides the following technical solutions:

[0010] A reinforcement-soil interface friction characteristic test device, comprising:

[0011] The main body of the test platform is equipped with a fiber soil model box, a portable fiber fixing device, a traction pulley device and a horizontal observation device on the top, and a test bench leveling device on the bottom;

[0012] The fiber soil model box is located at one end of the test platform body and is used to load the test soil embedded with fibers, and a gap is formed on the front side thereof for the fibers to pass through;

[0013] A traction pulley device is located at the other end of the test platform body, and the traction force of the water drop loading device is transmitted to the portable fiber fixing device through the pulley;

[0014] A portable fiber fixing device, one end of which clamps the fibers extending out of the fiber soil model box, and the other end of which is connected to the load through the traction rope and pulley of the traction pulley device, and moves between the fiber soil model box and the traction pulley device under the drive of the water drop loading device;

[0015] A vertical loading device, located at one side of the fiber-soil model box, is used to apply longitudinal pressure to the top plate of the fiber-soil model box;

[0016] The water drop loading device is located on one side of the traction pulley device and is used to provide horizontal traction to drive the portable anchoring device to move in the horizontal direction, thereby pulling the fiber out of the soil; a laser displacement sensor is provided on its bracket, and the laser displacement sensor is connected to the computer for communication. The relationship between traction and displacement is plotted through the displacement-time curve relationship, and the load-displacement-time relationship is obtained;

[0017] The horizontal observation devices are distributed at the four corners of the top of the test platform body and are used to observe the balance state of the test platform body and adjust the balance through the test platform leveling device.

[0018] Furthermore, the fiber-soil model box includes a fiber-soil model box body, a top plate, a plug-in type ordinary baffle, and a plug-in type baffle with a seam. The front side and the top of the fiber-soil model box body are open. The plug-in type ordinary baffle and the plug-in type baffle with a seam top plate are sequentially plugged into the front side of the fiber-soil model box body according to test requirements. After the front side of the fiber-soil model box body is installed, the top plate is installed on the top of the fiber-soil model box body.

[0019] Furthermore, the portable fiber fixing device includes a fiber anchor, an anchor lifting device and an anchor trolley, wherein the fiber anchor is composed of an anchor nut, an upper pressure plate, a lower base plate and an anchor screw rod; gaskets are provided at the relative positions of the edges of the upper pressure plate and the lower base plate for clamping the fiber; after the fiber is inserted between the upper pressure plate and the lower base plate, the anchor nut is then fixed on the anchor screw rod, and the fiber anchor is fixed to the fiber by adjusting the anchor nut; then the height of the fiber anchor is adjusted to be consistent with the height of the fiber through the anchor lifting device and the anchor trolley is used to move it back and forth.

[0020] Furthermore, the test platform body is provided with a fiber-soil model box placement area, a horizontal pulling area, a traction pulley fixing area and a fiber-soil model box baffle. The fiber-soil model box placement area is used to place the fiber-soil model box and is limited by the fiber-soil model box baffle. The horizontal pulling area is the activity area of ​​the portable fiber fixing device. The traction pulley fixing area is used to fix the traction pulley device.

[0021] Furthermore, the water drop loading device includes a water tank bracket, a high water level water tank, a low water level water outlet tank, an automatic water level regulating device, an electrically controlled valve and a water outlet pipe; the high water level water tank and the low water level water outlet tank are located on the water tank bracket, one end of the low water level water outlet tank is connected to the water outlet pipe and the switch is controlled by a solenoid valve, the other end of the water outlet pipe is placed in a traction load bucket of a traction pulley device, the other end of the low water level water outlet tank is connected to the high water level water tank and the water level in the low water level water outlet tank is maintained stable through the automatic water level regulating device; the automatic water level regulating device is located inside the low water level water outlet tank, and is composed of a float, a connecting lever device and a piston, one end of the connecting lever device is connected to the float, and the other end is connected to the piston, and the piston moves up and down at the water outlet of the high water level water tank extending into the low water level water outlet tank through the sinking and floating of the float.

[0022] Furthermore, the connecting lever device includes a device support, a circular steel frame, stabilizing bolts and matching nuts, and an obstruction plate. The device support is fixed inside the low water level outlet tank. The circular steel frame is rotated on the device support through stabilizing bolts and matching nuts. The circular steel frame has two arms, which are respectively connected to the float and the piston. The obstruction plate is fixed on the side of the device support close to the float, and is used to limit the rotation angle of the circular steel frame.

[0023] Furthermore, the traction pulley device includes a pulley device fixed base, a pulley support, a pulley, a pulley height adjustment screw and a traction load bucket; a plurality of fixing holes are formed on the pulley device fixed base, which is fixed to the traction pulley fixing area of ​​the test platform body through the pulley anchoring screw; the pulley support is fixed on the pulley device fixed base, and its front side is flush with the front side of the pulley device fixed base; the pulley is rotatably connected to the inclined surface on the front side of the top of the pulley support, and the pulley height is adjusted by adjusting the height of the nut on the pulley height adjustment screw.

[0024] Furthermore, the test bench is equipped with a leveling device, including two upper and lower cylindrical sleeves of different diameters and a fine-tuning height table pad at the bottom; the sleeve is provided with a plurality of holes at equal distances, and the height of the test platform body is adjusted by screwing fixing bolts into the holes at different heights; the bottom of the sleeve is a screw rod, and the top of the fine-tuning height table pad is provided with a screw hole matching the screw rod, and the height is adjusted by rotating the fine-tuning height table pad.

[0025] Furthermore, the vertical loading device includes a vertical height adjustment screw and a foot pad, a holding cross bar and a fixing nut, a deflection elimination reaction force pad, and a load weight; the bottom of the vertical height adjustment screw is fixed to the ground through the foot pad; one end of the holding cross bar moves up and down on the top of the vertical height adjustment screw through the fixing nut, and the load weight is hung on the ring at the other end of the holding cross bar through the top hook and the traction rope; the deflection elimination reaction force pad includes a triangular bracket, a bearing and a reaction force pad, the top of the triangular bracket slides in the slideway of the holding cross bar, and the reaction force pad is rotatably connected to the lower end of the triangular bracket through a bearing to ensure that the top plate of the fiber soil model box coincides with the action point of the reaction force pad and is always vertically downward.

[0026] On the other hand, the present invention also provides a method for testing the friction characteristics of the reinforcement-soil interface, using any of the above-mentioned devices and the following steps:

[0027] S1. Turn on the electric switch of the electric control valve and the laser displacement sensor, and the water in the low water level outlet tank flows into the traction load bucket from the outlet pipe at a uniform speed. The dead weight of the water droplets generates a downward pulling force, which is transmitted to the portable fiber fixing device through the traction rope and the traction pulley device, generating a horizontal pulling force on the portable fiber fixing device, thereby pulling the fiber;

[0028] S2. The displacement of the traction load bucket is synchronously collected by the laser displacement sensor into the computer to observe the movement of the fiber. When the fiber is pulled out, the test is stopped.

[0029] S3. The relationship between displacement and time is synchronously collected by the laser displacement sensor, and then the relationship between displacement and traction is calculated, and then the friction characteristics of the fiber-soil interface are obtained.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention adopts a vertical loading device, and the overburden loading method is convenient and simple, easy to operate, and the overburden load size is not limited. The vertical loading device can apply vertical pressure to the soil in the fiber-soil model box, on the one hand, to achieve the consolidation of the reshaped soil; on the other hand, by changing the size of the overburden load, the influence of normal pressure on the mechanical properties of the fiber-reinforced soil bar-soil interface can be studied.

[0032] (2) The use of an angle-eliminating reaction force pad device in the vertical loading device can avoid eccentric compression during vertical load loading.

[0033] (3) A water drop loading device is used to provide horizontal traction. The water drop loading device uses a double water tank, in which an automatic water level adjustment device is used to ensure that the water level in the water outlet tank remains unchanged. The water outlet tank is equipped with an electric control valve to control the water flow speed. By controlling the water flow speed, the uniformity, continuity and real-time measurability of the horizontal traction can be achieved.

[0034] (4) The present invention adopts water drop loading. Since the flow rate is constant, the weight of the water drop is a function of time, and the relationship between displacement and time can be monitored in real time by a laser displacement sensor. After corresponding conversion, the load-displacement-time relationship can be finally obtained, thereby realizing rapid data collection and processing.

[0035] (5) A portable fiber fixing device is used, which is easy to operate, can reduce the disturbance of the test operation to the anchoring fiber, and can achieve simultaneous fixing of multiple groups of fibers.

[0036] (6) The fiber soil model box of the present invention is equipped with multiple sets of plug-in type seam baffles, which can realize flexible arrangement of multiple sets of fibers in the horizontal and vertical directions, with different anchoring spacings and anchoring depths according to the test plan.

[0037] (7) The test bench is equipped with a leveling device and a horizontal observation device to ensure that the test bench is always in a horizontal state during the test, thereby reducing the impact of the test bench tilt on the test results.

[0038] In summary, the reinforcement-soil interface friction characteristics test device and test method provided by the present invention can obtain the shear stress-strain relationship between the fiber and soil interface under different loads by adjusting the size of the overlying load, thereby obtaining test parameters such as the interface shear strength, interface cohesion, internal friction angle, shear displacement, etc., and can study the effects and mechanisms of the effects of parameters such as different soil qualities and different fiber types on the test by changing the soil type, soil properties, fiber type, etc., such as being used for the test study of the reinforcement-soil interface friction characteristics of fiber-reinforced soil to reveal the laws of stress and deformation at the reinforcement-soil interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0040] Figure 1 A three-dimensional diagram of a reinforcement-soil interface friction characteristic testing device provided in an embodiment of the present invention.

[0041] Figure 2 A front view of a reinforcement-soil interface friction characteristics testing device provided in an embodiment of the present invention.

[0042] Figure 3 A right view of a reinforcement-soil interface friction characteristics testing device provided in an embodiment of the present invention.

[0043] Figure 4A schematic diagram of a fiber soil model box provided in an embodiment of the present invention.

[0044] Figure 5 A schematic diagram of the baffle assembly and connection points of the fiber soil model box provided in an embodiment of the present invention.

[0045] Figure 6 A schematic diagram of a plug-in type seamed baffle of a fiber soil model box provided in an embodiment of the present invention.

[0046] Figure 7 A schematic diagram of a portable fiber fixing device provided in an embodiment of the present invention.

[0047] Figure 8 A schematic diagram of a fiber anchor provided in an embodiment of the present invention.

[0048] Fig. 9 A schematic diagram of the fiber anchoring effect provided by an embodiment of the present invention.

[0049] Fig.10 A schematic diagram of the main body of the test platform provided in an embodiment of the present invention.

[0050] Fig.11 A diagram of a water droplet loading device provided in an embodiment of the present invention.

[0051] Fig.12 A schematic diagram of the principle of an automatic water level regulating device provided in an embodiment of the present invention.

[0052] Fig.13 A schematic diagram of water injection of the automatic water level regulating device provided in an embodiment of the present invention.

[0053] Fig.14 A schematic diagram of a connecting lever device provided in an embodiment of the present invention.

[0054] Fig.15 A schematic diagram of the operation of the connecting lever provided in an embodiment of the present invention.

[0055] Fig.16 A schematic diagram of a traction sheave device provided in an embodiment of the present invention.

[0056] Fig.17 This is a front view of a traction sheave device provided by an embodiment of the present invention.

[0057] Fig.18 This is a right side view of the traction sheave device provided by an embodiment of the present invention.

[0058] Fig.19 A diagram showing the arrangement of the horizontal observation device provided in an embodiment of the present invention.

[0059] Fig. 20 A front view of a test bench provided in an embodiment of the present invention equipped with a leveling device.

[0060] Fig.21 Schematic diagram of a height-adjustable table mat provided in an embodiment of the present invention.

[0061] Fig. 22 A schematic diagram of a vertical loading device provided in an embodiment of the present invention.

[0062] Fig.23 A schematic diagram of a deflection-eliminating reaction force pad provided in an embodiment of the present invention.

[0063] Fig.24 A load weight plate and a weight diagram provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0064] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0065] like Figure 1-3 The present invention provides a reinforcement-soil interface friction characteristic test device, comprising a fiber soil model box 1, a portable fiber fixing device 2, a test platform body 3, a water drop loading device 4, a traction pulley device 5, a horizontal observation device 6, a test platform leveling device 7, a vertical loading device 8, a laser displacement sensor 9 and a computer 10.

[0066] (1) Fiber soil model box

[0067] The fiber soil model box 1 is located at one end of the test platform body and is used to load the test soil embedded with fibers. A gap is formed on the front side of the box for fibers to pass through. Figure 4 The fiber soil model box 1 is composed of four parts, namely, a top plate 1-1, a plug-in type common baffle 1-2, a plug-in type baffle with seams 1-3 and a fiber soil model box body 1-4.

[0068] like Figure 5 As shown in the figure, the front side and the top of the fiber soil model box are open, and the baffle adopts a plug-in type design. Different plug-in type seam baffles 1-3 (such as Figure 6 During the test, the plug-in type common baffles 1-2 can be combined arbitrarily according to the test requirements (number of fibers, fiber embedding position, fiber type, etc.), and plugged in the front side of the fiber soil model box body in sequence. The combination is flexible and can significantly improve the test efficiency. After the front side of the fiber soil model box body is installed, the top plate is installed on the top of the fiber soil model box body.

[0069] (2) Portable fiber fixing device

[0070] like Figure 7As shown. The portable fiber fixing device 2 consists of three parts, namely, a fiber anchor 2-1, an anchor lifting device 2-2 and an anchor trolley 2-3. The fiber anchor 2-1 consists of four parts, namely, an anchor nut 2-1-1, an upper pressure plate 2-1-2, a lower bottom plate 2-1-3 and an anchor screw rod 2-1-4. Figure 8 shown.

[0071] During the test, after the fiber is inserted, the upper pressure plate 2-1-2 covers the lower base plate 2-1-3, and the anchoring screw 2-1-4 extends from the reserved hole of the upper pressure plate 2-1-2. Then, the anchoring nut 2-1-1 is fixed on the anchoring screw 2-1-4. The anchoring nut 2-1-1 is adjusted to ensure that the fiber anchor 2-1 and the fiber will not slip during the test. Then, the height of the fiber anchor 2-1 is adjusted to be consistent with the fiber height through the anchor lifting device 2-2 to avoid the test error caused by the height difference between the two during the test. The fiber anchoring effect is shown in FIG. Fig. 9 shown.

[0072] (3) Test platform

[0073] The test platform body 3 has a fiber soil model box, a portable fiber fixing device, a traction pulley device and a horizontal observation device installed on the top, and a test platform leveling device installed on the bottom.

[0074] like Fig.10 As shown, the test platform body 3 includes a fiber soil model box placement area 3-1, a horizontal pulling area 3-2, a traction pulley fixing area 3-3 and a fiber soil model box baffle 3-4. The fiber soil model box placement area is used to place the fiber soil model box and is limited by the fiber soil model box baffle, the horizontal pulling area is the activity area of ​​the portable fiber fixing device, and the traction pulley fixing area is used to fix the traction pulley device.

[0075] (4) Water drop loading device

[0076] like Fig.11 As shown, the function of the water drop loading device 4 is to provide horizontal traction, thereby driving the portable anchoring device 2 to move horizontally, thereby pulling the fiber out of the soil.

[0077] The water drop loading device 4 is composed of 6 parts, namely a high water level water storage tank 4-1, a water level automatic regulating device 4-2, a low water level water outlet tank 4-3, an electric control valve 4-4, a water storage tank bracket 4-5 and a water outlet pipe 4-6.

[0078] The high water level storage tank and the low water level outlet tank are located on the water tank bracket. One end of the low water level outlet tank is connected to the outlet pipe and the switch is controlled by the solenoid valve. The other end of the outlet pipe is placed in the traction load bucket of the traction pulley device. The other end of the low water level outlet tank is connected to the high water level storage tank and the water level in the low water level outlet tank is maintained stable through the water level automatic adjustment device.

[0079] In order to eliminate the influence of flow rate changes caused by water level difference on test data, this device adopts double water tanks to control water level, ensuring that during the test, the water level in the low water level outlet tank 4-3 is maintained stable through the water level automatic adjustment device 4-2 to achieve uniform and continuous water discharge.

[0080] like Fig.12 As shown, the automatic water level regulating device 4-2 is located inside the low water level outlet tank and is composed of a float 4-2-1, a connecting lever device 4-2-2 and a piston 4-2-3.

[0081] like Fig.13 As shown, during the test, since the water level of the high water level water tank 4-1 is always higher than that of the low water level water tank 4-3, according to the communicating vessel principle, the piston 4-2-3 will have an upward water pressure, and the high water level water tank 4-1 will inject water into the low water level water tank 4-3 until the water level pushes the float 4-2-1 to reach the control water level line, the connecting lever device 4-2-2 reaches the maximum torsion angle, the piston 4-2-3 falls, and the water injection stops. After the electric control valve 4-4 is opened, the water level of the low water level water tank 4-3 drops, the water level decreases, and the float 4-2-1 sinks, causing the piston 4-2-3 to be lifted up again, and water injection continues until the water level reaches the control water level line again.

[0082] like Fig.14 As shown, the connecting lever device 4-2-2 consists of three parts, namely a circular steel frame 4-2-2-1, a piston 4-2-3 and a float 4-2-1 connected on the left and right sides respectively, a stabilizing bolt and a matching nut 4-2-2-2, and an obstruction plate 4-2-2-3. The circular steel frame is rotated on the device support through the stabilizing bolt and the matching nut. The circular steel frame has two arms, which are respectively connected to the float and the piston. The obstruction plate is fixed on the side of the device support close to the float and is used to limit the rotation angle of the circular steel frame. It can limit the circular steel frame 4-2-2-1 to produce a large inclination angle and prevent the piston 4-2-3 from being completely pulled out.

[0083] like Fig.15As shown in the figure, since the left limb port of the circular steel frame 4-2-2-1 is connected to the piston 4-2-3 by a rope, and the right limb port is directly connected to the float 4-2-1, the up and down floating of the float 4-2-1 will drive the right limb of the circular steel frame 4-2-2-1, indirectly causing the right limb of the circular steel frame 4-2-2-1 to swing up and down, affecting the rise and fall of the piston 4-2-3. When the water level is stable, the float 4-2-1 is above the control water level line, and the left and right limbs of the circular steel frame 4-2-2-1 are in level. When the ring steel frame 4-2-2-1 is in a balanced state, the rope of the left limb is loosened, the piston 4-2-3 falls, the water inlet is blocked, and the water injection is stopped; when the water level drops, the float 4-2-1 and the right limb of the ring steel frame 4-2-2-1 drop accordingly, causing the left limb of the ring steel frame 4-2-2-1 to lift up, the rope is tightened, driving the piston 4-2-3 to produce an upward displacement, the water inlet is unblocked, and water injection begins. When the water level reaches the control water level line again, the left and right limbs of the ring steel frame 4-2-2-1 are in a balanced state again, and the water injection is stopped.

[0084] (5) Traction pulley device

[0085] like Figure 16-18 As shown, the traction pulley device 5 is composed of 5 parts, namely, a pulley 5-1, a pulley height adjustment screw 5-2, a pulley support 5-3, a pulley device fixed base 5-4 and a traction load bucket 5-5. A plurality of fixing holes are formed on the pulley device fixed base. The pulley device fixed base 5-4 can be connected and fixed with the pulley anchor screw of the traction pulley fixing area 3-3 of the test platform body 3. The pulley support is fixed on the pulley device fixed base, and its front side is flush with the front side of the pulley device fixed base. The pulley is rotatably connected to the inclined surface on the front side of the top of the pulley support. The height of the pulley 5-1 can be indirectly adjusted by the height of the nut on the pulley height adjustment screw 5-2 to adapt to various test schemes with different required heights.

[0086] (6) Horizontal observation device

[0087] The horizontal observation device 6 is a small round universal level bead set at the four corners of the platform body. It can ensure that the entire platform is in a balanced state throughout the entire test phase by observing the balance device. The specific layout position is shown in Fig.19 , distributed at the four corners of the top of the test platform.

[0088] (7) The test bench is equipped with a leveling device

[0089] like Fig. 20As shown, the test bench is equipped with a leveling device 7 consisting of two cylindrical sleeves 7-1 with different diameters, a fine-adjustment height table pad 7-3 is installed at the bottom, and a plurality of equidistant holes 7-4 are provided on the sleeve. The height of the test platform body 3 can be adjusted as needed using a fixing bolt 7-2 to meet the requirements of the test plan. The bottom of the sleeve is a screw rod, and the top of the fine-adjustment height table pad is provided with a screw hole matching the screw rod. When fine-adjustment of the height is required, the height can be adjusted by rotating the fine-adjustment height table pad 7-3, as shown in FIG. Fig.21 shown.

[0090] (8) Vertical loading device

[0091] like Fig. 22 As shown, the vertical loading device 8 consists of four parts, namely, a vertical height adjustment screw and foot pad 8-1, a force holding cross bar and a fixing nut 8-2, a deflection elimination reaction force pad 8-3, and a load weight plate and weights 8-4.

[0092] As the load increases, the top plate 1-1 of the fiber soil model box and the bearing cross bar 8-2 will have a horizontal inclination angle, which will cause uneven force on the fibers in the fiber soil model box 1. In order to eliminate this effect, a deflection-eliminating reaction force pad 8-3 is specially designed, such as Fig.23 As shown, the triangular bracket 8-3-1 can slide freely on the bearing cross bar 8-2. Due to the existence of the bearing 8-3-2, the reaction pad 8-3-3 can have a certain twist angle in the horizontal direction, and can automatically adjust the inclination angle as the test proceeds, always ensuring that the top plate of the 1-1 fiber soil model box and the reaction pad 8-3-3 action point coincide with each other and always point vertically downward, eliminating the test error caused by the deflection angle. Fig.24 As shown, the load weight plate can be hung on the ring at the right end of the holding crossbar through the top hook.

[0093] (9) Data Collection

[0094] The laser displacement sensor 9 used in the present invention uploads data to the computer 10 synchronously through the software supporting the sensor, and the displacement-time curve relationship can be obtained. During the test, the laser displacement sensor 9 and the electric control valve 4-4 are opened at the same time. Since the designed water drop loading device 4 can ensure that the flow rate remains unchanged, the weight of the water drop is a function of time. Therefore, the relationship between the weight of the water drop (i.e., traction) and the displacement can be plotted through the displacement-time curve data uploaded by the laser displacement sensor 9, and finally the load-displacement-time relationship can be obtained. In addition, the computer 10 is added to integrate the collected data, which can maximize the rapid collection and processing of data.

[0095] The specific steps of the testing method provided by the present invention are as follows:

[0096] Preparation before testing:

[0097] (1) First, according to the test plan, such as the number, spacing and different embedding depths of fibers, the types and arrangements of the plug-in type ordinary baffles 1-2 and the plug-in type seamed baffles 1-3 are selected to assemble a complete fiber soil model box 1;

[0098] (2) Place the installed fiber-soil model box 1 in the fiber-soil model box placement area 3-1. Due to reasons such as uneven ground, the test platform body 3 may be uneven, affecting the test results. At this time, the platform height can be adjusted by observing the horizontal observation device 6 and adjusting the test platform leveling device 7 to keep the test platform body 3 level. During the entire test process, if the test platform is found to be uneven, it can be adjusted at any time.

[0099] (3) The test soil is placed in the fiber-soil model box 1 and compacted according to the test plan. When the test soil reaches the fiber burial depth, stop adding soil. According to the fiber burial depth, anchoring depth and fiber spacing in the test plan, one end of the fiber is laid at the corresponding position, and one end of the fiber extends out from the fiber hole of the plug-in type seam baffle 1-3. Continue to add test soil and compact it lightly. After the overlying soil layer reaches the burial depth required by the test plan, cover the top plate 1-1.

[0100] (4) By adjusting the vertical height adjustment screw in the vertical loading device 8 and the support cross bar and the fixing nut 8-2 on the foot pad 8-1, it is ensured that the top plate 1-1 of the fiber soil model box 1 is in vertical contact with the deflection elimination reaction force pad 8-3.

[0101] (5) The load weight plate 8-4 is hung on the ring at the right end of the holding crossbar 8-2 of the vertical loading device 8 through the top hook, and the number of weights to be applied and the consolidation time are determined according to the test plan, and the weights are applied to consolidate the soil;

[0102] (6) After the soil in the fiber-soil model box 1 is completely consolidated, the portable fiber fixing device 2 is placed in the horizontal drawing area 3-2 of the test platform body 3. According to the position of the fiber extending from the fiber holes of the plug-in type seam baffle 1-3 in step (3), the anchor lifting device 2-2 is adjusted to make the upper pressure plate 2-1-2 and the lower bottom plate 2-1-3 of the fiber anchor 2-1 consistent with the fiber burial depth.

[0103] (7) Use wooden blocks to clamp the anchor trolley 2-3 to prevent it from moving before the test.

[0104] (8) Extend the anchoring screw 2-1-4 from the reserved hole of the upper pressure plate 2-1-2, and then fix the anchoring nut 2-1-1 on the anchoring screw 2-1-4. Place the fiber extending from the fiber hole of the plug-in type seam baffle 1-3 in step (3) between the upper pressure plate 2-1-2 and the lower base plate 2-1-3. Adjust the anchoring nut 2-1-1 to ensure that the 2-1 fiber anchor and the fiber will not slip during the test. Fine-tune the 2-2 anchor lifting device to keep the fiber level.

[0105] (9) Install the traction pulley device 5 on the traction pulley fixing area 3-3 of the test platform body 3 and fix it with a nut. Then, adjust the nut under the pulley 5-1 in the traction pulley device 5 according to the horizontal position of the fiber, and use the traction rope to connect the portable fiber fixing device 2 with the traction load bucket 5-5 to ensure that the traction rope and the axis of the fiber are at the same horizontal height.

[0106] (10) Connect the laser displacement sensor 9 to the computer 10 and open the supporting software of the laser displacement sensor.

[0107] (11) After the 4-water drop loading device is installed, place the outlet pipe 4-6 in the 4-water drop loading device in the traction load bucket 5-5, and inject clean water into the 4-1 high water level water storage tank and the low water level water outlet tank 4-3. Note that the water level in the low water level water outlet tank 4-3 must be lower than the water level in the high water level water storage tank 4-1.

[0108] (12) Before starting the test, adjust the automatic water level regulating device 4-2 and remove the wooden block that is blocking the anchor trolley 2-3.

[0109] After the trial starts:

[0110] (1) Turn on the electric switch of the synchronous control electric control valve 4-4 and the laser displacement sensor 9. At this time, the water in the low water level water tank 4-3 will flow into the traction load bucket 5-5 from the water outlet pipe 4-6 at a uniform speed. The dead weight of the water droplets will generate a downward pulling force, which is transmitted to the portable fiber fixing device 2 through the traction rope and the traction pulley device 5, generating a horizontal pulling force on the portable fiber fixing device 2, thereby pulling the fiber.

[0111] (2) The displacement of the traction load bucket 5-5 is synchronously collected by the laser displacement sensor 9 to the computer 10 to observe the movement of the fiber. When the fiber is pulled out, the test is stopped.

[0112] (3) Since the water droplet flow rate is constant, the weight of the water in the traction load bucket 5-5 is a function of time. The relationship curve between displacement and time is synchronously collected by the 9-laser displacement sensor, and then the relationship between displacement and traction force is calculated, and then the friction characteristics of the fiber-soil interface are obtained.

[0113] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A reinforcement-soil interface friction characteristics test device, characterized in that: include: The main body of the test platform is equipped with a fiber soil model box, a portable fiber fixing device, a traction pulley device and a horizontal observation device on the top, and a test bench leveling device on the bottom; The fiber soil model box is located at one end of the test platform body and is used to load the test soil embedded with fibers, and a gap is formed on the front side thereof for the fibers to pass through; A traction pulley device is located at the other end of the test platform body, and the traction force of the water drop loading device is transmitted to the portable fiber fixing device through the pulley; A portable fiber fixing device, one end of which clamps the fiber extending out of the fiber soil model box, and the other end is connected to the load through the traction rope and pulley of the traction pulley device, and moves between the fiber soil model box and the traction pulley device under the drive of the water drop loading device; the portable fiber fixing device comprises a fiber anchor, an anchor lifting device and an anchor trolley, wherein the fiber anchor consists of an anchor nut, an upper pressing plate, a lower bottom plate and an anchor screw rod; gaskets are provided at the relative positions of the edges of the upper pressing plate and the lower bottom plate for clamping the fiber; after the fiber is inserted between the upper pressing plate and the lower bottom plate, the anchor nut is then fixed to the anchor screw rod, and the fiber anchor is fixed to the fiber by adjusting the anchor nut; then the height of the fiber anchor is adjusted to be consistent with the height of the fiber through the anchor lifting device, and the front and rear movement is achieved through the anchor trolley; A vertical loading device, located at one side of the fiber-soil model box, is used to apply longitudinal pressure to the top plate of the fiber-soil model box; The water drop loading device is located on one side of the traction pulley device and is used to provide horizontal traction to drive the portable anchoring device to move in the horizontal direction, thereby pulling the fiber out of the soil; a laser displacement sensor is provided on its bracket, and the laser displacement sensor is connected to the computer for communication, and the relationship between traction and displacement is plotted through the displacement-time curve relationship to obtain the load-displacement-time relationship; the water drop loading device includes a water tank bracket, a high water level water tank, a low water level water outlet tank, an automatic water level regulating device, an electric control valve and a water outlet pipe; the high water level water tank and the low water level water outlet tank are located in the water tank bracket. On the tank bracket, one end of the low water level outlet tank is connected to the outlet pipe and the switch is controlled by the solenoid valve, the other end of the outlet pipe is placed in the traction load bucket of the traction pulley device, the other end of the low water level outlet tank is connected to the high water level storage tank and the water level in the low water level outlet tank is maintained stable through the water level automatic adjustment device; the water level automatic adjustment device is located inside the low water level outlet tank, and is composed of a float, a connecting lever device and a piston, one end of the connecting lever device is connected to the float, and the other end is connected to the piston, and the piston moves up and down through the sinking and floating of the float to extend into the water outlet of the low water level outlet tank from the high water level storage tank; The horizontal observation devices are distributed at the four corners of the top of the test platform body and are used to observe the balance state of the test platform body and adjust the balance through the test platform leveling device.

2. The reinforcement-soil interface friction characteristics testing device according to claim 1 is characterized in that: The fiber soil model box comprises a fiber soil model box body, a top plate, a plug-in type common baffle, and a plug-in type baffle with seams. The front side and the top of the fiber soil model box body are open. The plug-in type common baffle and the plug-in type baffle with seams top plate are sequentially plugged into the front side of the fiber soil model box body according to test requirements. After the front side of the fiber soil model box body is installed, the top plate is installed on the top of the fiber soil model box body.

3. The reinforcement-soil interface friction characteristics testing device according to claim 1, characterized in that: The test platform body is provided with a fiber-soil model box placement area, a horizontal pulling area, a traction pulley fixing area and a fiber-soil model box baffle. The fiber-soil model box placement area is used to place the fiber-soil model box and is limited by the fiber-soil model box baffle. The horizontal pulling area is the activity area of ​​the portable fiber fixing device. The traction pulley fixing area is used to fix the traction pulley device.

4. The reinforcement-soil interface friction characteristics testing device according to claim 1, characterized in that: The connecting lever device includes a device support, a circular steel frame, stabilizing bolts and matching nuts, and an obstruction plate. The device support is fixed inside the low water level water outlet tank. The circular steel frame rotates on the device support through stabilizing bolts and matching nuts. The circular steel frame has two arms, which are respectively connected to the float and the piston. The obstruction plate is fixed on the side of the device support close to the float and is used to limit the rotation angle of the circular steel frame.

5. The reinforcement-soil interface friction characteristics testing device according to claim 1, characterized in that: The traction pulley device comprises a pulley device fixed base, a pulley support, a pulley, a pulley height adjustment screw and a traction load bucket; a plurality of fixing holes are formed on the pulley device fixed base, which is fixed to the traction pulley fixing area of ​​the test platform body through the pulley anchor screw; the pulley support is fixed to the pulley device fixed base, and its front side is flush with the front side of the pulley device fixed base; the pulley is rotatably connected to the inclined surface on the front side of the top of the pulley support, and the pulley height is adjusted by adjusting the height of the nut on the pulley height adjustment screw.

6. The reinforcement-soil interface friction characteristics testing device according to claim 1, characterized in that: The test bench is equipped with a leveling device, including two upper and lower cylindrical sleeves of different diameters and a fine-adjustment height table pad at the bottom; the sleeve is provided with a plurality of holes at equal distances, and the height of the test platform body is adjusted by screwing fixing bolts into the holes at different heights; the bottom of the sleeve is a screw rod, and the top of the fine-adjustment height table pad is provided with a screw hole matching the screw rod, and the height is adjusted by rotating the fine-adjustment height table pad.

7. The reinforcement-soil interface friction characteristics testing device according to claim 1, characterized in that: The vertical loading device includes a vertical height adjustment screw and a foot pad, a holding cross bar and a fixing nut, a deflection elimination reaction force pad, and a load weight; the bottom of the vertical height adjustment screw is fixed to the ground through the foot pad; one end of the holding cross bar moves up and down on the top of the vertical height adjustment screw through the fixing nut, and the load weight is hung on the ring at the other end of the holding cross bar through the top hook and the traction rope; the deflection elimination reaction force pad includes a triangular bracket, a bearing and a reaction force pad, the top of the triangular bracket slides in the slideway of the holding cross bar, and the reaction force pad is rotatably connected to the lower end of the triangular bracket through the bearing to ensure that the top plate of the fiber soil model box coincides with the action point of the reaction force pad and is always vertically downward.

8. A method for testing the friction characteristics of a reinforcement-soil interface, characterized in that: Using the device as described in any one of claims 1 to 7 and the following steps: S1. Turn on the electric switch of the electric control valve and the laser displacement sensor, and the water in the low water level outlet tank flows into the traction load bucket from the outlet pipe at a uniform speed. The dead weight of the water droplets generates a downward pulling force, which is transmitted to the portable fiber fixing device through the traction rope and the traction pulley device, generating a horizontal pulling force on the portable fiber fixing device, thereby pulling the fiber; S2. The displacement of the traction load bucket is synchronously collected by the laser displacement sensor into the computer to observe the movement of the fiber. When the fiber is pulled out, the test is stopped. S3. The relationship between displacement and time is synchronously collected by the laser displacement sensor, and then the relationship between displacement and traction is calculated, and then the friction characteristics of the fiber-soil interface are obtained.

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