Loading test device and method for simulating horizontal load of reinforced soil retaining structure

Abstract

The application provides a loading test device and method for simulating horizontal load of reinforced soil retaining structure, and belongs to the technical field of geotechnical engineering model test. The device comprises a model box, a counterforce frame, a horizontal loading structure, a loading plate and a reinforcement positioning assembly. The loading plate is provided with arrayed holes. The reinforcement positioning assembly comprises reinforcement, a fixing wire and a locking piece. One side of the reinforcement is fixed on the panel, and the other side is connected to the model box through the fixing wire. The locking piece is used for locking the fixing wire to keep the initial pre-tension of the reinforcement. The horizontal loading structure applies a horizontal load to the loading plate, and the action line deviates from the geometric center of the loading plate by a preset distance. The application applies continuous traction to the end of the reinforcement through the fixing wire, ensures that the reinforcement maintains the tension state throughout the process while omitting the filling of the non-reinforced area, accurately simulates the triangular or trapezoidal distributed horizontal soil pressure through eccentric loading, greatly reduces the filling workload, shortens the test period and reduces the equipment requirements.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering model testing technology, specifically to a loading test device and method for simulating horizontal loads on reinforced soil retaining structures. Background Technology

[0002] Reinforced soil retaining structures are widely used in slope protection and retaining wall construction in highway, railway, and water conservancy projects. In indoor scaled-down model tests, to study the interaction mechanism, deformation patterns, and overall stability of the retaining structure between the reinforcement and the fill, a large amount of soil is typically filled into the model box. A typical reinforced soil retaining structure can be divided into a reinforced zone (active zone) and an unreinforced zone (stable zone). The unreinforced zone is located behind the rupture surface, and its main function is only to provide horizontal static earth pressure to the reinforced zone; it does not directly participate in the interfacial friction and interlocking between the reinforcement and the fill.

[0003] Chinese Patent Publication No. CN112649304A discloses a test system and method for testing the load performance of a prefabricated reinforced soil retaining wall. The system includes a test model box, a load loading device, and a data acquisition device for collecting the deformation of the reinforced soil retaining wall under load. The test model box has an upper opening and at least one circumferential opening. A reinforced soil retaining wall is placed inside the test model box, located at the circumferential openings. The load loading device applies a vertical load to the reinforced soil retaining wall inside the test model box through the upper opening. This test system can effectively simulate and measure the changes of the reinforced soil retaining wall structure under dynamic and static loads and is easy to test. The test method is convenient to operate, simplifies the measurement data of the entire dynamic and static load simulation, and can obtain accurate load test data.

[0004] Traditional model test methods require complete filling of unreinforced soil areas, which brings many problems: (1) The amount of filling work is huge, especially for large scale models or high stress level tests. The filling, compaction and dismantling of soil is time-consuming and labor-intensive, and the test cycle is long; (2) The filling of unreinforced soil areas generates great lateral pressure on the side walls of the model box, which requires extremely high rigidity and strength of the model box, increasing the test cost and difficulty; (3) A large amount of filling makes the overall weight of the model too large, which is not convenient for moving and adjusting the test equipment.

[0005] However, there is currently no specialized loading device that can accurately simulate the horizontal load applied to the reinforced zone without filling the unreinforced soil area. If a horizontal loading device is simply used to apply force directly to the boundary of the reinforced zone, the ends of the reinforcement are prone to relaxation and retraction due to the lack of soil containment and restraint. This makes it impossible to maintain tension during loading, resulting in the reinforcement effect within the retaining structure not being fully realized, distorting the experimental data, and failing to accurately reflect the stress mechanism of the reinforcement in actual engineering.

[0006] Therefore, there is an urgent need to develop a special loading test device and method that can eliminate the need for backfill in unreinforced areas, accurately simulate horizontal loads, and ensure that the reinforcement remains under effective tension throughout the test. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the present invention provides a loading test device and method for simulating horizontal loads on reinforced soil retaining structures, so as to omit the backfilling work in the unreinforced area in the model test, reduce the amount of test work, and at the same time ensure the tension state of the reinforcement and the true performance of the reinforcement effect.

[0008] The test apparatus includes: a model box, a reaction frame, a horizontal loading structure, a loading plate, and a stiffener positioning assembly; The model box has openings on the top and one side, and a panel is fixedly installed on the opening side of the model box. The reaction frame is installed on the side of the model box opposite to the opening side. The loading plate is set inside the model box, and the loading plate divides the model box into a soil filling and reinforcement cavity. The soil filling and reinforcement cavity is located between the loading plate and the panel, and the soil filling and reinforcement cavity is filled with reinforced soil. The loading plate is provided with multiple arrayed holes. The rib positioning assembly includes ribs, fixing lines, and locking components. The ribs are laid in the backfill of the reinforced area. One side of the ribs is fixed to the inner side of the panel, and the other side of the ribs is connected to the fixing lines. The end of the fixing lines passes through holes and is connected to the model box. The locking components are set in holes on the loading plate. The locking components are used to connect the fixing lines and the ribs, so that the fixing lines tighten the ribs and keep the ribs under initial pretension. The horizontal loading structure is installed on the reaction frame, and the end of the horizontal loading structure is connected to the loading plate. The horizontal loading structure is used to apply a horizontal thrust to the loading plate, and the line of action of the horizontal thrust is offset downward by a predetermined distance relative to the geometric center of the loading plate.

[0009] Furthermore, the bottom of the horizontal loading structure is provided with a lifting adjustment mechanism to adjust the eccentricity of the horizontal thrust applied by the horizontal loading structure. This allows the loading test device to conduct horizontal load simulation tests on the reinforced zone under different working conditions.

[0010] Furthermore, simulation tests of horizontal loads on the reinforced zone under different working conditions were conducted, including simulation tests of horizontal loads on the reinforced zone without surcharge and simulation tests of horizontal loads on the top of the reinforced soil retaining structure with uniformly distributed surcharges. Simulation test of horizontal load on reinforced area during the test.

[0011] Furthermore, when simulating a test condition without overload, the eccentricity of the line of action of the resultant force... satisfy ; At this point, the pressure at the top edge of the loading plate is exactly zero, while the pressure at the bottom edge reaches its maximum value. This forms a standard triangular distribution; The resultant force applied by the horizontally loaded structure satisfy: ; When a uniformly distributed surcharge q is applied to the top of a reinforced soil retaining structure, the horizontal earth pressure exerted by the loading plate on the reinforced zone exhibits a trapezoidal distribution, with the maximum stress at the bottom. satisfy: ; Minimum stress at the top satisfy ; At this time, the eccentricity According to overload The filling parameters satisfy the following relationship: ; The resultant force applied by the horizontally loaded structure satisfy: ; In the formula: The vertical height of the loading plate. The horizontal width of the loading plate. The unit weight of the fill soil in the reinforced area, This is the coefficient of earth pressure at rest.

[0012] Furthermore, the horizontal loading structure is a hydraulic jack, one end of which is slidably mounted on the reaction frame, and the telescopic end of the hydraulic jack is connected to the loading plate. The bottom of the lifting adjustment mechanism is fixed on the reaction frame, and the top of the telescopic shaft of the lifting adjustment mechanism is provided with a lifting seat, and the hydraulic jack is fixed on the lifting seat.

[0013] Furthermore, a first sliding guide rail is fixedly provided on the reaction frame, a second sliding guide rail is provided on the loading plate, and a first sliding block and a second sliding block are respectively provided at both ends of the horizontal loading structure. The first sliding block is slidably disposed on the first sliding guide rail, and the second sliding block is slidably disposed on the second sliding guide rail.

[0014] Furthermore, the second sliding block is provided with a ball joint, and the horizontal loading structure is connected to the second sliding block through the ball joint.

[0015] Furthermore, the horizontal loading structure is provided with a loading main rod and two loading support rods at its end. The two loading support rods are symmetrically arranged on both sides of the loading main rod, and a second sliding block is provided at the end of both the loading main rod and the loading support rods.

[0016] Furthermore, the panel is provided with a plurality of first strain gauges and pressure sensors, wherein the pressure sensors are located on the inner side of the panel, the first strain gauges are used to measure the deformation at various points on the panel, and the pressure sensors are used to sense the soil pressure at various points on the panel. A second strain gauge is attached to the reinforcing bar, which is used to measure the axial strain of the reinforcing bar.

[0017] This invention also provides a loading test method for simulating horizontal loads on reinforced soil retaining structures. This method uses the aforementioned loading test apparatus for simulating horizontal loads on reinforced soil retaining structures. The method includes the following steps: S1: Construct a panel inside the model box to simulate the reinforced soil retaining structure; S2: Fill the reinforced area with soil in layers, and lay the reinforcing material layer by layer until the reinforced area reaches the predetermined height; after each layer of reinforcing material is laid, tighten the fixing line to generate a predetermined preload force on the reinforcing material, and then use locking devices to lock the fixing line to maintain the predetermined preload force on the reinforcing material. S3: Determine the test conditions. When simulating a non-overload condition, set the eccentricity. , working together Calculated using the following formula: ; When there is a uniformly distributed overload on the simulated wall top At that time, set , ; The resultant force F is calculated using the following formula: ; S4: Adjust the line of action of the resultant force of the horizontally loaded structure to an eccentricity below the geometric center of the loading plate. Location; Initiate the horizontal loading structure to apply a resultant force to the loading plate in the horizontal direction. This causes the loading plate to exert a corresponding triangular or trapezoidal distributed horizontal pressure on the reinforced area fill soil; S5: Monitor and record the deformation, pressure, and strain data of the reinforcement material at various points on the panel during the loading process, so as to analyze the stress-deformation characteristics of the reinforced soil retaining structure.

[0018] The beneficial effects of the loading test device and method for simulating horizontal loads on reinforced soil retaining structures according to the present invention are as follows: (1) The test apparatus includes a model box, a reaction frame, a horizontal loading structure, a loading plate, and a reinforcement positioning assembly. A panel is fixedly provided on the open side of the model box, the reaction frame is set on the side of the model box opposite to the open side, the loading plate is set inside the model box, and the horizontal loading structure is used to apply a horizontal thrust to the loading plate. The line of action of the horizontal thrust is offset downward by a preset distance relative to the geometric center of the loading plate. The test apparatus directly applies a horizontal load conforming to the triangular or trapezoidal distribution law to the reinforced area fill soil through the horizontal loading structure in conjunction with eccentric force application. This completely eliminates the need for a large amount of unreinforced soil filling in traditional model tests, greatly reduces the amount of filling work, shortens the test cycle, and reduces the requirements for the stiffness of the model box, thereby reducing the cost of test equipment.

[0019] (2) The reinforcement positioning component of the test device includes reinforcement, fixing line and locking member. The reinforcement is laid in the backfill of the reinforced area. One side of the reinforcement is fixed to the inner side of the panel, and the other side of the reinforcement is connected to the fixing line. The end of the fixing line passes through the hole and is connected to the model box. The locking member is set on the loading plate. The locking member is used to lock the connection between the fixing line and the reinforcement so that the reinforcement is taut and maintains the initial pretension. The test device clamps the end of the reinforcement through the fixing line and the locking member and fixes the end of the fixing line to the side wall of the model box. With the length adjustment function of the fixing line, the reinforcement is forced pretensioned during the loading process. The flexible feature of the fixing line avoids rigid constraints and additional bending moment, fundamentally solving the problem of reinforcement relaxation and shrinkage caused by the lack of unreinforced soil, and ensuring the real performance of the reinforcement effect. In addition, the fixing line of the test device passes through the hole in the loading plate. The position of the loading plate and the volume of the backfill reinforcement cavity are adjustable, so that the backfill volume is adjustable and highly flexible.

[0020] (3) During the loading process of the test device, the reinforcement is always kept in a tensile state. The displacement of the loading plate is directly converted into the relative displacement between the reinforcement and the backfill, which can truly reflect the stress mechanism of the reinforcement and the degree of reinforcement effect in actual engineering.

[0021] (4) This test method utilizes the classical principle of eccentric compression. It only requires shifting the line of action of the resultant force by the corresponding eccentricity to generate the required triangular or trapezoidal pressure distribution on the vertical loading plate. The structure is simple, easy to implement and control, and the test method provides the magnitude of the resultant force under different working conditions. eccentricity The quantitative relationship between the soil pressure parameters and the load parameters provides a clear theoretical basis for the design of loading parameters under different fill materials and different height conditions. Attached Figure Description

[0022] Figure 1 This is a first three-dimensional structural schematic diagram of a loading test device for simulating horizontal loads on reinforced soil retaining structures according to the present invention.

[0023] Figure 2 This is a second three-dimensional structural schematic diagram of a loading test device for simulating horizontal loads on reinforced soil retaining structures according to the present invention.

[0024] Figure 3 This is a partial structural schematic diagram of a loading test device for simulating horizontal loads on a reinforced soil retaining structure according to the present invention.

[0025] Figure 4 for Figure 3 The right view.

[0026] Figure 5 This is a partial structural diagram of the horizontal loading structure of the second sliding block connected to the ball joint in the loading test device for simulating horizontal loads on a reinforced soil retaining structure according to the present invention.

[0027] Figure 6 This is a cross-sectional view of a loading test device for simulating horizontal loads on a reinforced soil retaining structure according to the present invention.

[0028] Figure 7 This is a schematic diagram of the connection between the reinforcing bars and the fixing line in simulating the horizontal load of a reinforced soil retaining structure according to the present invention.

[0029] Figure 8 This is a schematic diagram of the mechanical model of triangular distributed pressure under no-overload conditions in the loading test device for simulating horizontal loads on reinforced soil retaining structures according to the present invention.

[0030] Figure 9 This is a schematic diagram of a mechanical model of trapezoidal pressure distribution under overload conditions for a loading test device of a reinforced soil retaining structure to simulate horizontal loads.

[0031] Figure 10 This is a comparison diagram of the lateral deformation of the support structure under different working conditions and under reinforced and unreinforced conditions when the horizontal load is applied under different working conditions by the loading test device of this invention through simulation test using finite difference numerical calculation software.

[0032] In the above diagram: 100-Model box, 110-Anchor plate, 120-Fastening sleeve, 130-Adjusting nut, 140-Rotating connector, 200-Reaction frame, 300-Horizontal loading structure, 310-Lifting seat, 320-Lifting adjustment mechanism, 330-First sliding guide rail, 340-First sliding block, 350-Loading main rod, 360-Loading push plate, 400-Loading plate, 410-Hole, 420-Second sliding guide rail, 421-Second sliding block, 430-Spherical hinge, 500-Reinforced area backfill, 600-Panel, 700-Reinforcing material, 800-Fixing line, 900-Locking component. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] 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 the invention and simplifying the description, and do not 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 the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Please refer to Figures 1 to 10 The loading test device for simulating horizontal load on reinforced soil retaining structure according to the present invention includes: model box 100, reaction frame 200, horizontal loading structure 300, loading plate 400 and reinforcement positioning assembly. The model box 100 has openings on its top and one side. A panel 600 is fixedly provided on the opening side of the model box 100. The panel 600 is used to simulate the exterior facade of the support structure. The reaction frame 200 is disposed on the side of the model box 100 opposite to the opening side, and is used to provide support for the loading reaction force. The side plate of the model box 100 opposite to the panel 600 is an anchor plate 110.

[0037] The loading plate 400 is disposed inside the model box 100. The loading plate 400 divides the model box 100 into a soil-filled and reinforced cavity. The soil-filled and reinforced cavity is located between the loading plate 400 and the panel 600. The soil-filled and reinforced cavity is filled with reinforced fill 500. The area inside the soil-filled and reinforced cavity is the reinforced area. The loading plate 400 is a high-strength steel plate. The loading plate 400 is provided with a plurality of arrayed holes 410.

[0038] The reinforcement positioning assembly includes a reinforcement 700, a fixing line 800, and a locking member 900. The reinforcement 700 is laid in the backfill 500 of the reinforcement area. One side of the reinforcement 700 is fixed to the inner side of the panel 600, and the other side of the reinforcement 700 is connected to the fixing line 800. The end of the fixing line 800 passes through the hole 410 and is connected to the anchor plate 110 of the model box 100. The locking member 900 is disposed in the hole 410 on the loading plate 400. The locking member 900 is used to lock the fixing line 800 and the reinforcement 700 so that the reinforcement 700 is taut and maintains the initial pretension.

[0039] The fixing line 800 is made of high-strength, low-elongation flexible wire, such as steel wire rope, nylon braided rope or carbon fiber bundle, and the reinforcing material 700 is any one of geogrid, geotextile, steel-plastic composite strip or strip reinforcing material.

[0040] During installation, first clamp one end of the fixing line 800 to the end of the reinforcing bar 700 using the locking device 900. Then, pass the free end of the fixing line 800 through the corresponding hole 410 on the loading plate 400 and lead it to the fixing point on the side wall of the model box 100. Next, tighten the fixing line 800 and adjust its effective length so that the fixing line 800 is in a taut state. In this way, the reinforcing bar 700 is pulled by the fixing line 800 and obtains initial pretension, maintaining a pre-tensioned state.

[0041] Because the anchoring end of the fixing line 800 is independent of the loading plate 400 and fixedly connected to the side wall of the model box 100, during subsequent loading, as the loading plate 400 moves forward, the fixing line 800 remains taut, and the ends of the reinforcing bars 700 are continuously constrained, preventing slackening or retraction due to the movement of the loading plate 400. The displacement of the loading plate 400 is directly converted into relative displacement between the reinforcing bars 700 and the backfill, thus fully utilizing the reinforcement effect within the retaining structure. The flexible nature of the fixing line 800 also avoids rigid constraints and additional bending moments on the loading plate 400, ensuring smooth force application along the horizontal direction.

[0042] A horizontal loading structure 300 is installed on a reaction frame 200. The end of the horizontal loading structure 300 is connected to a loading plate 400. The horizontal loading structure 300 is used to apply a horizontal thrust to the loading plate 400 to simulate the horizontal static earth pressure provided by the unreinforced soil. The line of action of the horizontal thrust is offset downward by a preset distance from the geometric center of the loading plate 400.

[0043] The bottom of the horizontal loading structure 300 is provided with a lifting adjustment mechanism 320 to adjust the eccentricity of the horizontal thrust applied by the horizontal loading structure 300. This allows the loading test device to conduct horizontal load simulation tests on the reinforced zone under different working conditions.

[0044] Simulation tests of horizontal loads on reinforced zones under different working conditions include simulation tests of horizontal loads on reinforced zones without surcharge and simulation tests of horizontal loads on the top of reinforced soil retaining structures with uniformly distributed surcharges. Simulation test of horizontal load on reinforced area during the test.

[0045] In simulated no-overload test conditions, the line of action of the resultant force applied by the horizontal loading structure 300 does not pass through the geometric center of the loading plate 400, but is offset downward by a predetermined distance, causing the loading plate 400 to generate a triangularly distributed horizontal pressure on the reinforced fill 500 from zero at the top to a maximum at the bottom. According to the classical eccentric compression condition of a rectangular rigid contact surface, when the eccentricity of the line of action of the resultant force... Equal to the vertical height of the loading plate 400 At 1 / 6 of the maximum pressure, the pressure at the top edge of the loading plate 400 is exactly zero, while the pressure at the bottom edge reaches its maximum value. This forms a standard triangular distribution.

[0046] When simulating a test condition without overload (condition 1), the eccentricity of the line of action of the resultant force. satisfy ; At this point, the pressure at the top edge of the loading plate 400 is exactly zero, while the pressure at the bottom edge reaches its maximum value. This forms a standard triangular distribution; The resultant force applied by the horizontal loading structure 300 satisfy: ; In the formula: The vertical height of the loading plate is 400 (i.e., the height of the reinforced area fill is 500). This refers to the horizontal width of the loading plate 400 (i.e., the width of the model box 100). The coefficient of earth pressure at rest. Fill the reinforced area with 500 units of soil.

[0047] Thus, the point of application of the resultant force is located at a height of H / 6 below the geometric center of the loading plate 400, that is, at a height of H / 3 from the bottom of the loading plate 400. This loading method can accurately simulate the distribution law of horizontal earth pressure that increases linearly with depth in the unreinforced soil by simply adjusting the vertical position of the point of application of the resultant force. The mechanical concept is clear and the structural implementation is simple.

[0048] The simulated reinforced soil retaining structure has a uniformly distributed surcharge at the top. Under load condition 2, the horizontal earth pressure generated by the 400mm loading plate on the reinforced area is distributed in a trapezoidal shape, with the maximum stress at the bottom. satisfy: , Minimum stress at the top satisfy ; At this time, the eccentricity According to overload The filling parameters satisfy the following relationship: ; The resultant force applied by the horizontal loading structure 300 satisfy: ; By precisely adjusting the point of application of the resultant force to the aforementioned eccentricity position, a horizontal pressure conforming to the trapezoidal distribution pattern can be automatically generated on the loading plate 400, realistically simulating the overload condition at the top of the wall.

[0049] In a preferred embodiment, the horizontal loading structure 300 is a hydraulic jack, one end of which is slidably mounted on the reaction frame 200, and the telescopic end of the hydraulic jack is connected to the loading plate 400. The lifting adjustment mechanism 320 is an electric lifting push rod or a hydraulic lifting push rod. The bottom of the lifting adjustment mechanism 320 is fixed to the reaction frame 200, and the top of the telescopic shaft of the lifting adjustment mechanism 320 is provided with a lifting seat 310, on which the hydraulic jack is fixed. This facilitates the adjustment of the height of the horizontal loading structure 300. A first sliding guide rail 330 is fixedly mounted on the reaction frame 200, and a second sliding guide rail 420 is provided on the loading plate 400. A first sliding block 340 and a second sliding block 421 are respectively provided at both ends of the horizontal loading structure 300. The first sliding block 340 is slidably mounted on the first sliding guide rail 330, and the second sliding block 421 is slidably mounted on the second sliding guide rail 420. This facilitates the adjustment of the height of the horizontal loading structure 300, thereby adjusting the eccentricity of the resultant force line. .

[0050] Furthermore, the second sliding block 421 is provided with a ball joint 430, and the horizontal loading structure 300 is connected to the second sliding block 421 through the ball joint 430. The ball joint 430 ensures the resultant force applied by the horizontal loading structure 300. level.

[0051] In a preferred embodiment, the horizontal loading structure 300 is provided with a loading push plate 360 ​​at its end. A loading main rod 350 and two loading support rods are fixedly connected to the loading push plate 360. The two loading support rods are symmetrically arranged on both sides of the loading main rod 350. The ends of the loading main rod 350 and the loading support rods are provided with second sliding blocks 421. The anchor plate 110 is provided with corresponding clearance grooves for the loading main rod 350 and the two loading support rods to pass through.

[0052] In a preferred embodiment, the panel 600 is provided with a plurality of first strain gauges and pressure sensors, wherein the pressure sensors are located on the inner surface of the panel 600, the first strain gauges are used to measure the deformation at various points on the panel 600, and the pressure sensors are used to sense the soil pressure at various points on the panel 600; a second strain gauge is attached to the reinforcing bar 700, and the second strain gauge is used to measure the axial strain of the reinforcing bar 700. The first strain gauges, pressure sensors, and second strain gauges are used to record the stress-deformation characteristics of the panel 600 and the reinforcing bar 700. The first strain gauges, pressure sensors, and second strain gauges are all prior art, and their structures are not described in detail here.

[0053] In a preferred embodiment, the anchor plate 110 is provided with a fixing line tensioning mechanism and a tensioning threaded hole. A fastening sleeve 120 is threadedly connected to the tensioning threaded hole. The outer wall of the fastening sleeve 120 is threadedly connected to the threaded hole. A rotating connector 140 is fixed to the end of the fixing line 800. The rotating connector 140 is rotatably connected to the fastening sleeve 120, that is, the rotating connector 140 moves axially with the fastening sleeve 120 and can rotate relative to the fastening sleeve 120. An adjusting nut 130 is fixed to the outer end of the fastening sleeve 120. Rotating the adjusting nut 130 can adjust the tension length of the fixing line 800, thereby adjusting the tension of the reinforcing bar 700. The locking element 900 is located in the hole 410 on the loading plate 400. Its outer wall has a certain elasticity. The locking element 900 can slide in the hole. The locking element 900 can be a cylindrical jacket structure. Its two ends lock the fixing line 800 and the reinforcing bar 700 respectively to realize the connection between the two.

[0054] During the experiment, when filling the reinforced area with 500 mm of soil in layers, for each layer of geogrid reinforcement material 700 mm, one end of the fixing wire 800 was clamped to the edge of the reinforcement material 700 mm via a locking device 900. Then, the fixing wire 800 was tightened to bring it into a taut state. At this time, the reinforcement material 700 mm was pulled by the fixing wire 800 and obtained initial pretension, maintaining a pre-tensioned state.

[0055] During the forward displacement of the loading plate 400 by the hydraulic jack, the fixing line 800 remains taut, and the edges of the reinforcing bar 700 are connected to the fixing line 800, preventing slackening or retraction due to the movement of the loading plate 400. The movement of the loading plate 400 directly leads to a relative displacement tendency between the reinforcing bar 700 and the reinforced backfill 500, generating friction between the reinforcing bar 700 and the soil, thus entering a high-tension state. This "passive tensioning" effect is consistent with the mechanical behavior of the reinforcing bar 700 being pulled out by the soil in real engineering, thereby fully utilizing the frictional interlocking effect of the reinforced soil. The flexible characteristics of the fixing line 800 avoid interference from rigid constraints and additional bending moments on the loading plate 400, ensuring smooth force application along the horizontal direction. The holes 410 on the loading plate 400 allow the fixing line 800 to be finely adjusted within the holes, preventing jamming.

[0056] This invention also provides a loading test method for simulating horizontal loads on reinforced soil retaining structures. This method uses the aforementioned loading test apparatus for simulating horizontal loads on reinforced soil retaining structures. The method includes the following steps: S1: Construct a panel 600 inside the model box 100 to simulate the reinforced soil retaining structure; S2: Fill the reinforced area with soil 500 in layers, and lay the reinforcing material 700 layer by layer until the reinforced area soil 500 reaches the predetermined height; after each layer of reinforcing material 700 is laid, tighten the fixing line 800 so that the reinforcing material 700 generates a predetermined preload, and then use the locking device 900 to lock the fixing line 800 so that the reinforcing material 700 maintains the predetermined preload. S3: Determine the test conditions. When simulating a non-overload condition, set the eccentricity. , working together Calculated using the following formula: ; When there is a uniformly distributed overload on the simulated wall top At that time, set , ; combined efforts Calculated using the following formula:

[0057] S4: Adjust the line of action of the resultant force of the horizontal loading structure 300 to an eccentricity below the geometric center of the loading plate 400. Position; Initiate the horizontal loading structure 300, which applies a resultant force to the loading plate 400 in the horizontal direction. This causes the loading plate 400 to generate a corresponding triangular or trapezoidal distributed horizontal pressure on the reinforced fill 500; S5: Monitor and record the deformation, pressure value and strain data of the reinforcement 700 at various points on the panel 600 during the loading process, so as to analyze the stress and deformation characteristics of the reinforced soil retaining structure. S6: After the test, unload the horizontal loading structure 300, disassemble the fixing line 800 and locking parts 900 layer by layer, remove the fill soil 500 in the reinforced area, and the test is completed.

[0058] refer to Figure 8 In this embodiment, the reinforced area is filled with soil at a height of 500 mm. The model box is 1m long and 100mm wide. The value is 1m, simulating a non-overloaded working condition, heavy-duty. The coefficient of earth pressure at rest is 17 kN / m³. The maximum horizontal earth pressure is 0.426. The required resultant force is 7.24 kPa. The formula is used to calculate the required resultant force. Eccentricity The loading plate 400 generates a triangularly distributed horizontal pressure of 7.24 kPa from top to bottom on the reinforced fill 500, realistically simulating the horizontal earth pressure on the unreinforced soil under no overload conditions.

[0059] Please see Figure 9 There are overload conditions (trapezoidal distribution): When the experiment needs to simulate a uniformly distributed overload on the top of the wall Under the working condition, the reinforced area is filled with soil to a height of 500 mm. ,width Severe coefficient of earth pressure at rest It is 0.426.

[0060] It can be calculated to obtain: Maximum stress at the bottom ; Minimum stress at the top ; Magnitude of resultant force Eccentricity .

[0061] The hydraulic jack's force-applying axis is located 0.077m below the geometric center of the loading plate 400. When a horizontal thrust of 7.88kN is applied, a trapezoidal horizontal pressure of 4.26kPa at the top and 11.50kPa at the bottom is generated on the loading plate 400, accurately simulating the earth pressure distribution when there is an overload at the top of the wall.

[0062] Throughout the experiment, the invention cleverly eliminated the need for the large and cumbersome unreinforced soil filling in the model test by combining the design of "horizontal eccentric loading + flexible line tensioning and locking". This greatly reduced the amount of filling work and ensured the authenticity of the mechanical response mechanism of the reinforcement material 700. It can flexibly simulate various working conditions such as no overload and overload, and has significant engineering practical value and promotion prospects.

[0063] Figure 10 To verify the simulation accuracy of this device, Example 1 (without overload) was used. ) and Example 2 (with overload) Using the same parameters as in Example 1 as an example, a traditional test model of the complete unreinforced soil filling zone was established using the finite difference software FLAC3D for comparative analysis. It can be seen that regardless of whether there is an overload at the top of the retaining structure, the method proposed in this invention can effectively simulate the horizontal load generated by the unreinforced soil in the reinforced soil retaining structure. Furthermore, it is verified that maintaining the tension of the reinforcement at 700° by fixing the line 80° can significantly improve the accuracy of the test results.

[0064] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A loading test device for simulating horizontal loads on reinforced soil retaining structures, characterized in that, include: Model box (100), reaction frame (200), horizontal loading structure (300), loading plate (400) and stiffener positioning assembly; The model box (100) has openings on the top and one side, and a panel (600) is fixedly provided on the opening side of the model box (100). The reaction frame (200) is provided on the side of the model box (100) opposite to the opening side. The loading plate (400) is disposed inside the model box (100). The loading plate (400) divides the model box (100) into a soil filling and reinforcement cavity. The soil filling and reinforcement cavity is located between the loading plate (400) and the panel (600). The soil filling and reinforcement cavity is filled with reinforced fill soil (500). The loading plate (400) is provided with a plurality of arrayed holes (410). The reinforcement positioning assembly includes reinforcement (700), fixing line (800), and locking member (900). The reinforcement (700) is laid in the backfill (500) of the reinforcement area. One side of the reinforcement (700) is fixed to the inner side of the panel (600), and the other side of the reinforcement (700) is connected to the fixing line (800). The end of the fixing line (800) passes through the hole (410) and is connected to the model box (100). The locking member (900) is set in the hole (410) of the loading plate (400). The locking member (900) is used to connect the fixing line (800) and the reinforcement (700), so that the fixing line (800) pulls the reinforcement (700) taut and the reinforcement (700) maintains the initial pretension. A horizontal loading structure (300) is mounted on a reaction frame (200), and the end of the horizontal loading structure (300) is connected to a loading plate (400). The horizontal loading structure (300) is used to apply a horizontal thrust to the loading plate (400), and the line of action of the horizontal thrust is offset downward by a predetermined distance relative to the geometric center of the loading plate (400).

2. The loading test device for simulating horizontal loads on reinforced soil retaining structures according to claim 1, characterized in that, The bottom of the horizontal loading structure (300) is provided with a lifting adjustment mechanism (320) to adjust the eccentricity of the horizontal thrust applied by the horizontal loading structure (300). This allows the loading test device to conduct horizontal load simulation tests on the reinforced zone under different working conditions.

3. The loading test device for simulating horizontal loads on reinforced soil retaining structures according to claim 2, characterized in that, Simulation tests of horizontal loads in reinforced areas under different working conditions include simulation tests of horizontal loads in reinforced areas without surcharges and simulation tests of horizontal loads in reinforced areas when there is a uniformly distributed surcharge q at the top of the reinforced soil retaining structure.

4. The loading test device for simulating horizontal loads on reinforced soil retaining structures according to claim 3, characterized in that: The eccentricity of the line of action of the resultant force under simulated no-overload test conditions satisfy ； At this point, the pressure at the top edge of the loading plate (400) is exactly zero, while the pressure at the bottom edge reaches its maximum value. This forms a standard triangular distribution; The resultant force applied by the horizontal loading structure (300) satisfy: ； The simulated reinforced soil retaining structure has a uniformly distributed surcharge at the top. At that time, the horizontal earth pressure generated by the loading plate (400) on the reinforced zone is distributed in a trapezoidal shape, with the maximum stress at the bottom. satisfy: ； Minimum stress at the top satisfy ； At this time, the eccentricity According to overload The filling parameters satisfy the following relationship: ； The resultant force applied by the horizontal loading structure (300) satisfy: In the formula: The vertical height of the loading plate (400) The lateral width of the loading plate (400) The fill material for the reinforced area has a density of (500) units. This is the coefficient of earth pressure at rest.

5. The loading test device for simulating horizontal loads on reinforced soil retaining structures according to claim 2, characterized in that: The horizontal loading structure (300) is a hydraulic jack, one end of which is slidably mounted on the reaction frame (200), and the telescopic end of the hydraulic jack is connected to the loading plate (400). The bottom of the lifting adjustment mechanism (320) is fixed on the reaction frame (200), and the top of the telescopic shaft of the lifting adjustment mechanism (320) is provided with a lifting seat (310), and the hydraulic jack is fixed on the lifting seat (310).

6. The loading test device for simulating horizontal loads on reinforced soil retaining structures according to claim 1, characterized in that: The reaction frame (200) is fixedly provided with a first sliding guide rail (330), the loading plate (400) is provided with a second sliding guide rail (420), and the horizontal loading structure (300) is provided with a first sliding block (340) and a second sliding block (421) at both ends respectively. The first sliding block (340) is slidably disposed on the first sliding guide rail (330), and the second sliding block (421) is slidably disposed on the second sliding guide rail (420).

7. The loading test device for simulating horizontal loads on reinforced soil retaining structures according to claim 6, characterized in that: The second sliding block (421) is provided with a ball joint (430), and the horizontal loading structure (300) is connected to the second sliding block (421) through the ball joint (430).

8. The loading test device for simulating horizontal loads on reinforced soil retaining structures according to claim 1, characterized in that: The horizontal loading structure (300) is provided with a loading main rod (350) and two loading support rods at its end. The two loading support rods are symmetrically arranged on both sides of the loading main rod (350). The ends of the loading main rod (350) and the loading support rods are provided with a second sliding block (421).

9. The loading test device for simulating horizontal loads on reinforced soil retaining structures according to claim 1, characterized in that: The panel (600) is provided with a plurality of first strain gauges and pressure sensors, wherein the pressure sensors are located on the inner side of the panel (600), the first strain gauges are used to measure the deformation at various points of the panel (600), and the pressure sensors are used to sense the soil pressure at various points of the panel (600). A second strain gauge is attached to the reinforcing bar (700), which is used to measure the axial strain of the reinforcing bar (700).

10. A loading test method for simulating horizontal loads on reinforced soil retaining structures, characterized in that, The loading test apparatus for simulating horizontal loads on reinforced soil retaining structures as described in any one of claims 1-9 is used; the method includes the following steps: S1: Construct a panel (600) inside the model box (100) to simulate the reinforced soil retaining structure. S2: Fill the reinforced area with soil in layers (500), and lay the reinforcing material (700) layer by layer until the reinforced area fill (500) reaches the predetermined height; wherein, after each layer of reinforcing material (700) is laid, tighten the fixing line (800) so that the reinforcing material (700) generates a predetermined amount of preload; S3: Determine the test conditions. When simulating no overload conditions, set the eccentricity. , working together Calculated using the following formula: ； When there is a uniformly distributed overload on the simulated wall top At that time, set , ； combined efforts Calculated using the following formula: S4: Adjust the line of action of the resultant force of the horizontal loading structure (300) to be eccentrically below the geometric center of the loading plate (400). Position; activate the horizontal loading structure (300) to apply a resultant force to the loading plate (400) in the horizontal direction. This causes the loading plate (400) to generate a corresponding triangular or trapezoidal distributed horizontal pressure on the reinforced fill (500); S5: Monitor and record the deformation, pressure value and strain data of the reinforcement (700) at various points on the panel (600) during the loading process, so as to analyze the stress and deformation characteristics of the reinforced soil retaining structure.

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