A long-term mechanical performance test device for buried ABR pipelines under freeze-thaw cycle conditions

Abstract

A long-term mechanical performance test device for buried ABR pipelines under freeze-thaw cycle conditions includes a loading device, the loading device includes a containing box, a vertical loading mechanism, and a horizontal loading mechanism; the vertical loading mechanism includes a support and a connecting rod rotatably connected to the support, one end of the connecting rod is provided with a loading body, and the other end of the connecting rod is rotatably connected to a first rack, and the first rack is connected to the cover of the containing box through a power transmission gear and a second rack; the horizontal loading mechanism includes a retaining wall, and the retaining wall and the baffle are connected by a threaded rod and a nut. By tightening the nut, a horizontal load that varies linearly in the height direction can be applied to the baffle. The force applied to the loading body can be multiplied by the support and the connecting rod, and the applied vertical load is constant, and no additional loading is required during the test. By applying a horizontal load that varies linearly in the height direction to the soil, the authenticity of the test simulation is further improved.

Description

Technical Field

[0001] The present invention belongs to the field of pipeline engineering, and in particular relates to a long-term mechanical performance testing device for buried ABR pipelines under freeze-thaw cycle conditions. Technical Background

[0002] As a crucial medium in water resource management, water pipelines are widely used in water distribution, water supply and drainage, and agricultural irrigation. However, due to the inherent quality of the pipes and the impact of natural disasters, existing water pipelines are increasingly prone to aging, cracking, and leakage. In particular, polyvinyl chloride (PVC) pipes, due to their severe brittleness at low temperatures in winter and poor impact resistance, pose significant risks to water supply projects. To address this, newly developed acrylic ester-blended polyvinyl chloride (ABR) pipes, with their superior physical and mechanical properties, offer a more stable pipeline option for water supply projects.

[0003] In order to further measure the compressive strength and durability of the ABR pipe, tests were carried out on it based on the simulation of corresponding working conditions to quantify its performance parameters.

[0004] Patent CN112098220A discloses a self-balancing constant-loading device for studying the creep performance of steel tube concrete components. This invention uses a jack as the source of the constant load. Because concrete shrinkage and creep cause the load to decrease, a pressure sensor is used to monitor the load. When the load falls below a certain threshold, the jack is adjusted to a constant load, a process known as supplemental loading. While this invention can stabilize the load within a certain range, intermittent adjustment of the jack can cause load fluctuations, and multiple adjustments can seriously affect the test progress.

[0005] Patent CN107515232A discloses a freeze-thaw cycle test device, which places a specimen box in a temperature-controlled box. A pressure loading mechanism is provided on the top of the specimen box to measure changes in the physical and mechanical properties of the soil under the action of freeze-thaw cycles and vertical pressure. Although this invention simulates freeze-thaw cycles in cold regions and vertical stress conditions of rock and soil, it does not consider the migration of water inside the soil during the freeze-thaw cycle, and does not provide corresponding technical measures for the technical problem of how to set up a water replenishment device to ensure the internal moisture content of the soil. Therefore, the invention lacks a key factor (soil moisture content) in the simulation of freeze-thaw cycles, resulting in a large discrepancy between the entire test conditions and the actual working conditions, resulting in errors in the accuracy of the test results.

[0006] From the above, the existing technology has the following technical problems:

[0007] (1) Lack of adaptive reloading function. When the specimen is subjected to axial load under the action of the jack, it will be compressed and deformed. Then the interaction force between the specimen and the jack will decrease or even disappear, resulting in the specimen being unable to be continuously subjected to a constant load. Therefore, the existing technology detects the pressure. When the pressure change exceeds the threshold, it is necessary to manually adjust the jack for reloading so that the axial load reaches the preset value again. The load applied to the specimen using the above loading method fluctuates within a certain range, and it cannot be guaranteed that the specimen is subjected to a constant load. In addition, for freeze-thaw cycle test conditions, the continuous reloading operation will also destroy the temperature environment.

[0008] (2) Due to the lack of water replenishment devices, the moisture in the unfrozen area in the center of the soil migrates to the surrounding frozen areas, causing the moisture content in the center of the soil to change significantly, affecting the final test results.

[0009] (3) Lack of horizontal load, especially for pipelines buried underground, which must bear not only vertical soil pressure but also horizontal soil pressure. Lack of horizontal pressure will also affect the accuracy of pipeline bearing capacity test. Summary of the Invention

[0010] In view of this, the present invention intends to provide a long-term mechanical properties test device for buried ABR pipelines under freeze-thaw cycle conditions to solve the problems in the prior art of the need for continuous supplementary vertical loads and the lack of horizontal loads.

[0011] In order to achieve the above object, the present invention provides the following technical solutions:

[0012] A long-term mechanical performance test device for buried ABR pipelines under freeze-thaw cycle conditions includes a loading device, which includes a receiving box, a vertical loading mechanism and a horizontal loading mechanism. The receiving box includes rotatable baffles on both sides, the top of the baffle is provided with a baffle rotating shaft, the bottom surface of the baffle is inclined upward from the outside to the inside, and a wedge-shaped block is provided below the baffle to match the bottom surface of the baffle; the vertical loading mechanism is located on one side of the receiving box, the vertical loading mechanism includes a support and a connecting rod rotatably connected to the support, the end of the connecting rod away from the support is provided with a loading body, and the connecting rod close to the support is provided with a loading body. One end of the first rack is rotatably connected to the first rack, and the first rack is connected to the cover plate of the receiving box through a force transmission gear and a second rack. The meshing portion of the first rack is away from the connecting rod, and a rotation space is reserved between the first rack and the connecting rod, so that the first rack can rotate counterclockwise. An elastic supporting component is provided inside the rotating space, and the elastic supporting component connects the first rack and the connecting rod; the horizontal loading mechanism includes retaining walls located on both sides of the receiving box, and the retaining wall and the baffle are connected by threaded rods and nuts. By tightening the nuts, a horizontal load that changes linearly along the height direction can be applied to the baffle.

[0013] Beneficial effects:

[0014] (1) Compared with the prior art, on the one hand, the force acting on the load body can be multiplied by the supports and connecting rods; on the other hand, the vertical load applied by the vertical loading mechanism is constant, and no additional loading is required during the test.

[0015] (2) By adding a horizontal loading mechanism, a horizontal load that changes linearly along the height direction can be applied to the soil, further improving the authenticity of the test simulation.

[0016] Furthermore, it also includes a freeze-thaw device, which includes a temperature cycle test box, and the temperature cycle test box includes a temperature control box. The containing box and the vertical loading mechanism are both located inside the temperature control box.

[0017] Beneficial effect: freeze-thaw cycle test conditions can be simulated by adjusting the temperature in the temperature cycle test chamber.

[0018] Furthermore, a plurality of horizontal secondary beams are arranged at intervals along the height direction on the outer side surface of the baffle, and a plurality of main beams perpendicular to the secondary beams are arranged outside the secondary beams.

[0019] The beneficial effect is that it can ensure that when an external load is applied to the baffle, the load can act more evenly on the entire baffle, thereby effectively avoiding stress concentration.

[0020] Furthermore, the cover plate is divided into an upper plate body and a lower plate body connected to the upper plate body, and the lower plate body can penetrate deep into the interior of the storage box.

[0021] Beneficial effect: the upper plate can limit the downward movement of the cover plate and facilitate the removal of the cover plate; the lower plate is in direct contact with the soil, transferring a uniformly distributed load to the soil.

[0022] Furthermore, the second rack is located above the cover plate, and the second rack is fixedly connected to the cover plate via a second rack fixing seat, and the second rack fixing seat is located at the center of the cover plate.

[0023] Beneficial effect: the second rack is connected to the cover plate through the second rack fixing seat, and the contact area between the second rack and the cover plate is increased.

[0024] Furthermore, a second rack support unit is provided on the back of the second rack, and the second rack support unit includes a support rod and a slide groove. The fixed end of the support rod is fixedly connected to the back of the second rack, and the free end of the support rod is slidably connected to the slide groove, and the slide groove is fixedly connected to the side wall of the temperature control box.

[0025] Beneficial effect: the second rack support unit can provide support force for the second rack to prevent the second rack from deforming, and the support unit can slide with the second rack to provide continuous support for the second rack.

[0026] Furthermore, a side of the retaining wall facing away from the baffle is perpendicular to the horizontal plane, and a side of the retaining wall facing the baffle is inclined inward from top to bottom.

[0027] Beneficial effect: strengthen the anti-overturning ability of the retaining wall and prevent the retaining wall from turning over along the wall foot due to excessive force.

[0028] Furthermore, the water replenishing mechanism includes a sealed box and a water replenishing bottle located inside the sealed box. The water replenishing bottle is connected to the containing box through a water pipe. A water tank for replenishing the water replenishing bottle is provided above the water replenishing bottle. The water outlet of the water tank is connected to an infusion tube, and a flow rate regulator is provided on the infusion tube.

[0029] Beneficial effect: the water supply mechanism provides continuous water supply to the soil, and the water supply flow rate can be adjusted by the flow regulator to meet the test needs to a greater extent.

[0030] Furthermore, the interior of the holding box is filled with soil and an ABR pipe. The ABR pipe is located at the center of the holding box. The ABR pipe is horizontal and its extension direction is parallel to the baffle.

[0031] Beneficial effect, ensuring that the ABR tube is evenly stressed.

[0032] Furthermore, the water outlet end of the water pipe is divided into multiple branch pipes directly below the ABR pipe. The multiple branch pipes all rise vertically around the outer side surface of the ABR pipe. The water outlets of the branch pipes are vertical, and the apex of the branch pipe outlets is on the same horizontal plane as the top opening of the water replenishment bottle.

[0033] Beneficial effect: diverting the water pipe into multiple branches can increase the water outlet area, and the vertical state of the water outlet of the water pipe can effectively prevent the soil from entering the water outlet pipe under the action of vertical load and causing blockage of the pipe mouth. In addition, the upper vertex of the water outlet is at the same horizontal plane as the top opening of the water replenishment bottle, thereby realizing pressure-free water replenishment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to make the purpose, technical solutions and beneficial effects of the present invention more clear, the present invention provides the following drawings for illustration:

[0035] Figure 1 This is a schematic diagram of the overall structure of a long-term mechanical properties test device for buried ABR pipelines under freeze-thaw cycle conditions in Example 1 of the present invention (the front baffle of the containing box and the sealing box are hidden).

[0036] Figure 2 for Figure 1 Front view of the device (hiding the front baffle of the storage box and the sealed box).

[0037] Figure 3 This is a front view of the storage box and the horizontal loading mechanism in the first embodiment of the present invention (the front baffle of the storage box is hidden).

[0038] Figure 4 This is a front view of the support base in Example 1 of the present invention.

[0039] Figure 5 for Figure 4 A cross-sectional view in the middle AA direction (viewed from top to bottom) showing the internal structure of the support base.

[0040] Figure 6 Schematic diagram of the fixing plate in the first embodiment of the present invention.

[0041] Figure 7 Schematic diagram of the structure of the baffle shaft in embodiment 1 of the present invention.

[0042] Figure 8 Schematic diagram of the structure of the baffle in Example 1 of the present invention.

[0043] Figure 9 for Figure 3 The enlarged view of point A1 in the middle is used to show the positional relationship between the wedge block and the baffle.

[0044] Figure 10 Schematic diagram of the wedge block in Example 1 of the present invention.

[0045] Figure 11 This is a front view of the cover plate in Example 1 of the present invention.

[0046] Figure 12 This is a left side view of the cover plate in Example 1 of the present invention.

[0047] Figure 13 This is a bottom view of the cover plate in Example 1 of the present invention.

[0048] Figure 14 Schematic diagram of the structure of the support in embodiment 1 of the present invention.

[0049] Figure 15 This is a structural schematic diagram of the connecting rod and the first rack in Example 1 of the present invention, used to illustrate the positional relationship and connection relationship between the connecting rod and the first rack.

[0050] Figure 16 for Figure 15 Front view of .

[0051] Figure 17 Schematic diagram of the structure of the gear fixing rod in embodiment 1 of the present invention.

[0052] Figure 18 It is a left view of the power transmission gear in embodiment 1 of the present invention.

[0053] Figure 19 for Figure 18 The cross-sectional view in the middle BB direction is used to show the limit groove inside the power transmission gear.

[0054] Figure 20 Schematic diagram of the structure of the second rack support unit in embodiment 1 of the present invention.

[0055] Figure 21 This is a front view of the support rod in Example 1 of the present invention.

[0056] Figure 22 This is a left view of the support rod in Example 1 of the present invention, used to show the support rod shaft and pulley at the end of the support rod.

[0057] Figure 23 Schematic diagram of water migration inside soil during a unidirectional freeze-thaw cycle.

[0058] Figure 24 Schematic diagram of water migration inside soil under three-way freeze-thaw in Example 1 of the present invention.

[0059] The following are marked in the accompanying drawings:

[0060] Freeze-thaw device 1, temperature cycle test chamber 11, temperature control chamber 111, support base 1111, chamber support rod 112, loading device 2, accommodating box 21, fixing plate 211, limiting groove 2111, baffle shaft 212, limiting protrusion 2121, baffle 213, secondary beam 2131, main beam 2132, threaded groove 21321, wedge block 214, cover plate 215, upper plate 2151, lower plate 2152, rubber strip 216, vertical loading mechanism 22, support 221, fixing shaft 2211, connecting rod 222, through hole 2221, connecting rod shaft 2222, loading body 223, first rack 224 , rotating space 225, limiting spring 226, force transmission gear 227, limiting groove 2271, gear fixing rod 228, limiting block 2281, second rack 229, second rack fixing seat 2291, second rack support unit 2292, support rod 22921, support rod rotating shaft 22922, pulley 22923, slide 22924, horizontal loading mechanism 23, retaining wall 231, threaded rod 232, nut 233, water supply mechanism 24, sealing box 241, sealing box support rod 242, water supply bottle 243, water pipe 244, water tank 245, infusion tube 246, flow rate regulator 247, ABR pipeline 3, soil 4 DETAILED DESCRIPTION

[0061] Example 1, see Figure 1-Figure 24 .

[0062] like Figure 1As shown, a long-term mechanical performance test device for buried ABR pipelines under freeze-thaw cycle conditions includes a freeze-thaw device 1 and a loading device 2 located inside the freeze-thaw device 1.

[0063] like Figure 1-Figure 3 As shown, the freeze-thaw device 1 includes a temperature cycle test box 11. It should be noted that in this embodiment, the model of the temperature cycle test box 11 is XT5405FSC, which includes an upper temperature control box 111 and a lower box support rod 112. The four box support rods 112 provide support for the temperature control box 111. The temperature control box 111 is in the shape of a rectangular parallelepiped. The bottom plate of the temperature control box 111 is bolted as shown. Figure 2 、 Figure 4 The support base 1111 shown in FIG. 1 has a cross-section as shown in FIG. Figure 5 The lattice shape shown can provide support for the accommodating box 21 through the support base 1111 and increase the contact area between the accommodating box 21 and the temperature control box 111, thereby reducing local stress and effectively preventing the bottom plate of the temperature control box 111 from being deformed or even damaged due to excessive load.

[0064] The loading device 2 includes: Figure 1-Figure 3 The container 21, vertical loading mechanism 22, horizontal loading mechanism 23 and water replenishing mechanism 24 are shown. Figure 3 As shown, in this embodiment, the container 21 is used to fill the soil 4. The container 21 is a cube, with a support base 1111 as the bottom plate of the container 21. Two opposite fixing plates 211 are set along the width direction of the temperature cycle test chamber 11. The bottom of the fixing plate 211 is welded to the temperature support base 1111. The top of the two fixing plates 211 is opened as shown in FIG. Figure 6 The limiting groove 2111 shown in FIG. 21 is formed by the baffle shaft 212. Figure 7 The two end limiting protrusions 2121 are rotatably connected to the fixed plate 211, and the side of the baffle shaft 212 is welded as shown. Figure 8 The baffle 213 shown in FIG. 2 has a width smaller than the spacing between the fixing plates 211. In a natural state, the back of the baffle 213 and the side of the fixing plate 211 are in the same plane, and the side of the baffle 213 and the front of the fixing plate 211 are glued together as shown in FIG. Figure 6 、 Figure 8 The rubber strip 216 shown can effectively improve the sealing performance of the receiving box 21 .

[0065] The two fixing plates 211, the two baffles 213 and the support base 1111 together form the box structure of the container 21. It should be emphasized that in this embodiment, the angle between the bottom surface of the baffle 213 and the horizontal plane is 4°, and it tilts upward from the outside to the inside.

[0066] Below the baffle 213 is provided a Figure 9 、 Figure 10 The wedge block 214 shown in this embodiment has a triangular cross-section, and the angle between the top surface of the wedge block 214 and the horizontal plane is equal to the angle between the bottom surface of the baffle 213 and the horizontal plane. The arrangement of the wedge block 214 allows the baffle 213 to rotate inward about the baffle axis 212, thereby limiting the rotation of the baffle 213 and preventing the baffle 213 from rotating too far. Furthermore, when the bottom surface of the baffle 213 is in full contact with the top surface of the wedge block 214, the baffle 213 can be ensured to rotate to a stable state, and the sealing of the contact surface between the two can be guaranteed.

[0067] In addition, the back of the baffle 213 is welded as shown Figure 8 The illustrated secondary beams 2131 and main beams 2132 have seven horizontal secondary beams 2131 welded to the back of the baffle 213 and spaced apart along its height. Vertical main beams 2132 are welded to the outer sides of the secondary beams 2131, with two other main beams spaced apart along their lengths. It should be noted that in this embodiment, the outer sides of the main beams 2132 are provided with spaced apart threaded grooves 21321 along their heights. The threaded grooves 21321 are located at the intersection of the main beams 2132 and the secondary beams 2131. This arrangement of the main beams 2132 and secondary beams 2131 ensures that when external loads are applied to the baffle 213, the loads are applied relatively evenly across the entire baffle 213, effectively preventing stress concentration within the baffle 213.

[0068] The upper opening of the container 21 is provided with a Figure 11-13 The illustrated cover plate 215 has its bottom surface in direct contact with the soil 4. In this embodiment, the cover plate 215 comprises an upper plate 2151 and a lower plate 2152 welded to the upper plate 2151. The upper plate 2151 is rectangular and has a cross-sectional dimension larger than the upper opening of the container 21. It should be emphasized that the side of the lower plate 2152 corresponding to the baffle 213 is inclined inward from top to bottom, and the angle of inclination is consistent with the angle of inclination of the baffle 213 when it rotates to a stable position. The side of the lower plate 2152 corresponding to the fixed plate 211 is vertical. This arrangement allows the lower plate 2152 of the cover plate 215 to move vertically downward within the container 21, thereby applying a uniformly distributed load to the soil 4. Furthermore, the upper plate 2151 of the cover plate 215 provides a limit for the movement of the cover plate 215 and facilitates its removal.

[0069] like Figure 1-Figure 3As shown, the vertical loading mechanism 22 includes a support 221 located outside the baffle 213 and a connecting rod 222 rotatably connected to the support 221. In this embodiment, the cross section of the support 221 is rectangular, the bottom of the support 221 is threadedly connected to the bottom plate of the temperature control box 111, and the top of the support 221 is opened along the length direction of the rectangular cross section as shown in FIG. Figure 14 The opening shown in FIG. 2 has a cylindrical fixed shaft 2211 welded on both sides of the opening. The cross section of the connecting rod 222 is rectangular, and the corresponding surface perpendicular to the long side of the rectangle is opened as shown in FIG. Figure 15 、 Figure 16 Regarding the through hole 2221 shown, it is important to note that, in this embodiment, the through hole 2221 is located on one side of the connecting rod 222 and near the end of the connecting rod 222. The diameter of the through hole 2221 is consistent with the diameter of the fixed shaft 2211. The connecting rod 222 is rotatably connected to the support 221 via the fixed shaft 2211. The rectangular cross-section of the connecting rod 222 can enhance the load-bearing capacity of the connecting rod 222, especially its bending resistance.

[0070] One end of the connecting rod 222 away from the through hole 2221 is located on one side of the container 21, and the knot below the connecting rod 222 is as shown in FIG. Figure 2 The illustrated loading body 223, in this embodiment, is a weight of a certain mass. Under the weight of the loading body 223, the upper connecting rod 222 rotates clockwise downward about the fixed axis 2211. As the end of the connecting rod 222, away from the through-hole 2221, rotates clockwise downward about the fixed axis 2211, the end of the connecting rod 222, closer to the through-hole 2221, simultaneously rotates clockwise upward about the fixed axis 2211. The lever structure formed by the support 221 and the connecting rod 222 multiplies the weight of the loading body 223.

[0071] like Figure 15 As shown, the end of the connecting rod 222 near one end of the receiving box 21 is rotatably connected to the connecting rod shaft 2222, and the side of the connecting rod shaft 2222 is welded with a first rack 224, and the meshing portion of the first rack 224 is away from the support 221. It should be emphasized that in this embodiment, a gap is left between the first rack 224 and the end face of the connecting rod 222. Figure 15 、 Figure 16 The rotating space 225 shown in FIG. 2 is formed, and the back surface of the first rack 224 and the end surface of the connecting rod 222 are welded with a Figure 15 、 Figure 16 The four limiting springs 226 distributed in a rectangular shape as shown provide support force for the first rack 224 and play a limiting role through the limiting springs 226 .

[0072] A power transmission gear 227 is provided on one side of the meshing portion of the first rack 224. The power transmission gear 227 meshes with the first rack 224. In order to ensure the stable operation of the power transmission gear 227, a power transmission gear 227 is provided. Figure 17 The gear fixing rod 228 shown in the figure, in this embodiment, the gear fixing rod 228 is in a "7" shape, the horizontal section of the gear fixing rod 228 is parallel to the baffle shaft 212, and the end of the horizontal section of the gear fixing rod 228 close to the first rack 224 is welded as shown. Figure 17 The annular limit block 2281 shown in FIG. 2 is provided inside the power transmission gear 227 as shown in FIG. Figure 18 、 Figure 19 The limiting groove 2271 shown has a size consistent with the size of the limiting block 2281, and the force transmission gear 227 is rotatably connected to the gear fixing rod 228 through the limiting groove 2271; the vertical section of the gear fixing rod 228 is perpendicular to the support base 1111, and the bottom surface of the vertical section is welded to the top surface of the support base 1111.

[0073] Under the action of the loading body 223, the connecting rod 222 rotates upward in the clockwise direction around the fixed axis 2211 near one end of the receiving box 21, thereby driving the first rack 224 to move synchronously. By setting the first rack 224 and the connecting rod 222 to be rotatably connected, when the first rack 224 moves in the clockwise direction, it can also rotate counterclockwise around the connecting rod 2222. In addition, the limit spring 226 arranged between the back side of the first rack 224 and the connecting rod 222 can provide support for the first rack 224, thereby preventing the first rack 224 from getting stuck with the power transmission gear 227 and effectively ensuring the engagement and force transfer between the first rack 224 and the power transmission gear 227.

[0074] like Figure 3 As shown, a second rack 229 is provided on the side of the power transmission gear 227 away from the first rack 224. The second rack 229 is in a vertical state and meshes with the power transmission gear 227. The second rack 229 is connected to the cover plate 215 by a Figure 1 、 Figure 2 The second rack fixing seat 2291 shown is connected. In this embodiment, in order to ensure the uniform force of the cover plate 215, the second rack fixing seat 2291 is located at the center of the cover plate 215. The upper part of the second rack fixing seat 2291 is in the shape of a quadrangular pyramid, and the top surface of the quadrangular pyramid is welded to the bottom surface of the second rack 229, and the size of the top surface of the quadrangular pyramid is consistent with the shape and size of the bottom surface of the second rack 229; the lower part connected to the upper quadrangular pyramid is in the shape of a cuboid, and the top surface size of the lower cuboid is consistent with the bottom surface size of the upper quadrangular pyramid. The lower cuboid and the upper quadrangular pyramid are integrally formed, and the bottom surface of the lower cuboid is welded to the top surface of the cover plate 215. The transition of the lower cuboid can increase the welding area between the side surface of the second rack fixing seat 2291 and the top surface of the cover plate 21, thereby improving the welding stability.

[0075] The gear 228 can convert the clockwise upward movement of the first rack 224 into the vertical downward movement of the second rack 229. Since only the bottom surface of the second rack 229 is fixed, the upper and middle parts of the second rack 229 are easily deformed by the force when the gear 228 transmits the rotational force. Based on this, in order to improve the deformation resistance of the second rack 229, the following is specially set: Figure 20 The second rack support unit 2292 is shown. Figure 2 、 Figure 20-22 As shown, the second rack support unit 2292 includes a support rod 22921, a support rod rotating shaft 22922, a pulley 22923 and a slide groove 22924, which are arranged in sequence along the direction away from the gear. In this embodiment, the cross section of the support rod 22921 is rectangular. The end surface of the fixed end of the support rod 22921 is welded to the back of the second rack 229, and the fixed end surface is located at the center of the back of the second rack 229; the free end of the support rod 22921 is opened along the length of the rod as shown in FIG. Figure 22 The opening shown in FIG. 2 has a support rod shaft 22922 welded inside the opening, and a pulley 22923 is rotatably connected to the support rod shaft 22922; Figure 2 As shown, the back of the slide groove 22924 is welded to the side wall of the temperature control box 111, and the pulley 22923 is slidably connected to the slide groove 22924.

[0076] The support rod 22921 can provide support force for the second rack 229, effectively preventing the second rack 229 from being deformed by force. In addition, the support rod 22921 can also move vertically along the slide groove 22924 with the second rack 229 to ensure continuous support for the second rack 229.

[0077] like Figure 3 As shown, the horizontal loading mechanism 23 includes a retaining wall 231 located outside the retaining plate 213 and a threaded rod 232 and a nut 233 for applying load to the retaining plate 213. In this embodiment, the end surface of the retaining wall 231 is as shown in FIG. Figure 3 The trapezoid shown in FIG. 2 has a right-angled side, and the size of the back of the retaining wall 231 is consistent with the size of the back of the baffle 213. The front of the retaining wall 231 gradually tilts inward from top to bottom. It should be noted that in this embodiment, the retaining wall 231 is provided with threaded holes at intervals along the height direction, and the back of the main beam 2132 is provided with threaded holes at intervals. Figure 8 The threaded groove 21321 shown corresponds to the threaded hole 2311 and the thread 21321. The threaded rod 232 passes through the threaded hole 2311 and penetrates into the threaded groove 21321. By tightening the nut 233, a horizontal load is applied to the baffle 231.

[0078] By setting the front of the retaining wall 231 to gradually tilt outward from bottom to top, the anti-overturning ability of the retaining wall 231 can be effectively increased, and the retaining wall 231 can be prevented from flipping over along the bottom corner of the front due to excessive force; in addition, gradually adjusting the tightness of the thread 233 along the height direction can achieve the test condition of simulating the gradual increase of horizontal soil pressure from top to bottom.

[0079] In glacier action areas, mountainous areas and dynamic soil areas, taking one-way freezing as an example, the surface of the soil is affected by the ambient temperature, and the soil below it freezes. The depth direction is divided into the following: Figure 23 The frozen soil, frozen edge and unfrozen soil are shown in the figure. The freezing front is the part where the frozen edge and unfrozen soil are in contact (i.e. the 0°C isotherm). During the freezing process of the soil, the water in the soil continuously migrates upward under the action of the temperature gradient. In the natural environment, the lower soil can continuously provide water to the upper soil for water replenishment. In the indoor test, the soil is affected by cold sources in five directions, including the top surface and four side surfaces. When no external water replenishment is performed, Figure 24 As shown in the figure, the moisture in the middle and lower middle parts of the soil will gradually migrate to the outside, resulting in a decrease in the moisture content in the middle and lower middle parts of the soil, causing obvious discrepancies between the test simulation conditions and the natural environmental conditions, resulting in a large error in the final test results.

[0080] Based on this, in this embodiment, the following Figure 1 、 Figure 2 The water replenishing mechanism 24 shown in FIG. 2 includes a water replenishing bottle 243, a water pipe 244, and a water tank 245 that provides a continuous water source for the water replenishing bottle 243. In this embodiment, a device such as the one shown in FIG. 2 is provided on the side of the temperature cycle test chamber 11 near the chute 22924. Figure 1 The sealed box 241 is shown supported by a sealed box support rod 242 at the bottom. A water replenishment bottle 243 is cylindrical and open at the top. A through hole is formed at the bottom of the water replenishment bottle 243. The water inlet end of the water pipe 244 extends through the bottom plate of the sealed box 241 and into the water replenishment bottle 243. The water outlet end of the water pipe 244 extends through the temperature cycling test chamber 11 and the support base 111 and into the soil 4.

[0081] It should be noted that in this embodiment, considering the impact of the ABR pipe on the water migration path, the outlet of water pipe 244 is split directly below ABR pipe 3. The two branches rise vertically around the outer side of the ABR pipe and are glued to the side of the ABR pipe. Notably, the vertical position of the outlet of water pipe 244 effectively prevents soil from blocking the outlet pipe 244 when subjected to vertical pressure. Furthermore, the upper vertex of the outlet is aligned with the top opening of the water replenishment bottle 243, thus enabling pressure-free water replenishment.

[0082] In order to provide a continuous water source for the water replenishing bottle 243, a Figure 1 、 Figure 2 The water tank 245 shown has its top surface welded to the top plate of the sealed box 241. The bottom of the water tank 245 is connected to an infusion tube 246, which is equipped with a flow rate regulator 247. In this embodiment, both the infusion tube 246 and the flow rate regulator 247 can be medical infusion tubes and their corresponding flow rate regulators. The flow rate regulator 247 can adjust the water supply flow rate to better meet the test requirements.

[0083] During use, the soil 4 is first filled into the holding box 21. During the filling process, the ABR pipe and the water pipe 244 are buried at the designed depth, and the cover 215 is covered. Then, the vertical loading mechanism 22 and the horizontal loading mechanism 23 are installed, but the load body 223 does not need to be connected. Finally, a horizontal load is applied to the baffle 213 by tightening the nut 233. At the same time, a constant vertical load is applied to the cover 215 by connecting the load body 223 to the end of the connecting rod 222 away from the holding box 21. It should be emphasized that when the soil is frozen, the flow rate regulator 247 is opened to replenish water to the soil 4. During the thawing process of the frozen soil, the flow rate regulator 247 is closed.

[0084] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A long-term mechanical performance test device for buried ABR pipelines under freeze-thaw cycle conditions, characterized in that: The loading device includes a receiving box, a vertical loading mechanism and a horizontal loading mechanism. The receiving box includes baffles rotatable on both sides. The top of the baffle is provided with a baffle shaft. The bottom surface of the baffle is tilted upward from the outside to the inside. A wedge block is provided below the baffle that matches the bottom surface of the baffle. The vertical loading mechanism is located on one side of the receiving box. The vertical loading mechanism includes a support and a connecting rod rotatably connected to the support. The end of the connecting rod away from the support is provided with a loading body. The end of the connecting rod close to the support is rotatably connected to the first rack. The first The rack is connected to the cover plate of the receiving box through a power transmission gear and a second rack. The meshing portion of the first rack faces away from the connecting rod. A rotation space is reserved between the first rack and the connecting rod, so that the first rack can rotate counterclockwise. An elastic support component is provided inside the rotation space, and the elastic support component connects the first rack and the connecting rod; the horizontal loading mechanism includes retaining walls located on both sides of the receiving box, and the retaining walls are connected to the baffle by a threaded rod and a nut. By tightening the nut, a horizontal load that changes linearly along the height direction can be applied to the baffle.

2. The long-term mechanical properties testing device for buried ABR pipelines under freeze-thaw cycle conditions according to claim 1, characterized in that: It also includes a freeze-thaw device, which includes a temperature cycle test box. The temperature cycle test box includes a temperature control box. The containing box and the vertical loading mechanism are both located inside the temperature control box.

3. The long-term mechanical properties testing device for buried ABR pipelines under freeze-thaw cycle conditions according to claim 1, characterized in that: A plurality of horizontal secondary beams are arranged at intervals along the height direction on the outer side surface of the baffle, and a plurality of main beams perpendicular to the secondary beams are arranged outside the secondary beams.

4. The long-term mechanical properties testing device for buried ABR pipelines under freeze-thaw cycle conditions according to claim 1, characterized in that: The cover plate is divided into an upper plate body and a lower plate body connected to the upper plate body, and the lower plate body can penetrate into the interior of the accommodation box.

5. The long-term mechanical performance testing device for buried ABR pipelines under freeze-thaw cycle conditions according to claim 3, characterized in that: The second rack is located above the cover plate, and the second rack is fixedly connected to the cover plate via a second rack fixing seat, and the second rack fixing seat is located at the center of the cover plate.

6. The long-term mechanical properties testing device for buried ABR pipelines under freeze-thaw cycle conditions according to claim 2, characterized in that: A second rack support unit is provided on the back of the second rack, and the second rack support unit includes a support rod and a slide groove. The fixed end of the support rod is fixedly connected to the back of the second rack, and the free end of the support rod is slidably connected to the slide groove, and the slide groove is fixedly connected to the side wall of the temperature control box.

7. The long-term mechanical performance testing device for buried ABR pipelines under freeze-thaw cycle conditions according to claim 1, characterized in that: A side of the retaining wall facing away from the baffle is perpendicular to the horizontal plane, and a side of the retaining wall facing the baffle is inclined inward from top to bottom.

8. The long-term mechanical performance testing device for buried ABR pipelines under freeze-thaw cycle conditions according to claim 1, characterized in that: It also includes a water replenishment mechanism, which includes a sealed box and a water replenishment bottle located inside the sealed box. The water replenishment bottle is connected to the storage box through a water pipe. A water tank for replenishing the water replenishment bottle is provided above the water replenishment bottle. The water outlet of the water tank is connected to an infusion tube, and a flow rate regulator is provided on the infusion tube.

9. The long-term mechanical performance testing device for buried ABR pipelines under freeze-thaw cycle conditions according to claim 8, characterized in that: The interior of the holding box is filled with soil and an ABR pipe. The ABR pipe is located at the center of the holding box. The ABR pipe is horizontal and its extension direction is parallel to the baffle.

10. The long-term mechanical performance testing device for buried ABR pipelines under freeze-thaw cycle conditions according to claim 9, characterized in that: The water outlet end of the water pipe is divided into multiple branch pipes just below the ABR pipe. The multiple branch pipes rise vertically around the outer side of the ABR pipe. The water outlets of the branch pipes are vertical, and the apex of the branch pipe outlets is on the same horizontal plane as the top opening of the water replenishment bottle.

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