A rectangular pipe jacking model test device and test method

Abstract

The present invention discloses a rectangular pipe jacking model test device and a test method. The test device includes: a model box for loading test soil, and rectangular holes are correspondingly formed in the opposite first side and second side thereof; a pipe jacking replacement section which is partially or entirely inserted into the model box through the rectangular hole on the second side of the model box; pipe jacking pipe segments including pipe segment one and pipe segments two to N, wherein pipe segment one is connected to the end of the pipe jacking replacement section; a loading device arranged in front of the pipe jacking replacement section for pulling the pipe jacking replacement section, and during the pulling process, pipe segments two to N are synchronously jacked into pipe segment one in sequence from the rectangular hole on the first side of the model box. The test device of the present invention can carry out model tests of pipe jacking under complex conditions indoors. The test device simplifies and presents the excavation process, replaces the unloaded soil body, and realizes visual processing and dynamic monitoring of the surface settlement, pipe-soil contact and slurry diffusion conditions throughout the test process.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe jacking construction, and particularly relates to a rectangular pipe jacking model test device and a test method. Background Art

[0002] In recent years, with the acceleration of the process of underground space development and utilization, the pipe jacking method, as a key trenchless technology, has been widely applied. For rectangular pipe jacking, the existing relevant pipe jacking engineering theories are increasingly difficult to predict and cope with the construction impacts under complex engineering geological conditions. At the same time, on-site tests are often difficult to carry out.

[0003] Problems existing in the indoor model test of rectangular pipe jacking include that the excavation process is difficult to replicate, the unloaded soil is difficult to discharge, and the pipe-soil contact and slurry diffusion are difficult to display, etc. The existence of these problems makes the existing rectangular pipe jacking model test unable to accurately describe the engineering process, and there is also a large deviation between the theoretical prediction and the on-site measurement.

[0004] Therefore, it is necessary to propose a new rectangular pipe jacking model test device for indoor simulation tests that can achieve visual processing and dynamic monitoring. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the main purpose of the present invention is to provide a rectangular pipe jacking model test device and a test method to solve the problems in the prior art such as the difficulty in replicating the excavation process, the difficulty in discharging the unloaded soil, and the difficulty in displaying the pipe-soil contact and slurry diffusion.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention first proposes a rectangular pipe jacking model test device, including:

[0008] A model box for loading test soil, and rectangular holes are correspondingly provided on the opposite first side and second side thereof;

[0009] A pipe jacking replacement section that partially or completely penetrates into the model box from the rectangular hole on the second side of the model box, and is used to simulate the process of the pipe jacking machine excavating and discharging the excavated soil;

[0010] Pipe jacking pipe sections, including pipe section one and pipe sections two to N, wherein pipe section one is connected to the end of the pipe jacking replacement section;

[0011] A loading device is arranged in front of the pipe jacking replacement section, and is used to pull the pipe jacking replacement section, and during the pulling process, pipe sections two to N are synchronously jacked into pipe section one in sequence from the rectangular hole on the first side of the model box.

[0012] Preferably, the model box is a transparent lidless box, and the first side and the second side are detachable box panels, on which rectangular holes are provided.

[0013] Preferably, the pipe jacking replacement section includes four conventional splicing sections, and the four conventional splicing sections are spliced with each other to form a rectangular pipe jacking model with the smallest tunneling size.

[0014] Preferably, the cross-sections of the four conventional splicing sections are L-shaped, and the four L-shaped conventional splicing sections form the four corners of the rectangular pipe jacking model.

[0015] Preferably, the pipe jacking replacement section further includes at least one free splicing section arranged between two adjacent conventional splicing sections, and the free splicing section is symmetrically arranged on at least two opposite faces of the rectangular pipe jacking model. The conventional splicing section and the free splicing section are spliced with each other to form a rectangular pipe jacking model with a predetermined tunneling size.

[0016] Preferably, the splicing method of the conventional splicing section and the free splicing section is a slot splicing method, and slots and / or teeth are respectively provided at the splicing joints on both sides of the conventional splicing section and the free splicing section.

[0017] Preferably, the loading device includes a support platform, a sliding frame and a jacking mechanism. The support platform is arranged in front of the rectangular hole on the second side of the model box. The sliding frame is connected to the pipe jacking replacement section and can slide back and forth on the support platform under the jacking action of the jacking mechanism to pull the pipe jacking replacement section.

[0018] Preferably, guide rails are arranged on both sides of the support platform along the jacking direction; the sliding frame includes a force application rod connected to the pipe jacking replacement section, sliding blocks connected to both ends of the force application rod and cooperating with the guide rails on both sides, and a force application frame connected to the sliding blocks on both sides. The force application frame is arranged below the support platform.

[0019] Preferably, the jacking mechanism includes a reaction frame and an oil cylinder. The reaction frame is arranged across both sides of the support platform, and the oil cylinder is arranged on the reaction frame. The oil cylinder pushes and pulls the force application frame to drive the pipe jacking replacement section to move along the guide rail.

[0020] The present invention also provides a test method based on the above rectangular pipe jacking model test device, including:

[0021] S1: According to the pipe jacking pipe joint size, burial depth and quantity set in the test plan, select the model box corresponding to the rectangular hole and splice the corresponding pipe jacking replacement section;

[0022] S2: According to the soil parameters in the test plan, set the test similarity ratio on the pipe jacking replacement section to simulate the undisturbed soil body;

[0023] S3: Pull the pipe jacking replacement section on the support platform in advance, measure the dynamic friction coefficient between the pipe jacking replacement section and the support platform, and obtain the relationship curve between the extended length of the pipe jacking replacement section and the frictional force.

[0024] S4: Fill the test soil into the model box and complete the relevant pre - monitoring preparation work according to the test plan.

[0025] S5: When the test soil is filled to the bottom elevation of the pipe jacking replacement section, pass the pipe jacking replacement section through the rectangular holes on the second side and the first side of the model box in sequence, and insert it into the model box as a whole. Then continue to fill the test soil until the specified elevation.

[0026] S6: Connect the first pipe joint at the end of the pipe jacking replacement section and complete the relevant pre - monitoring preparation work according to the test plan.

[0027] S7: Start the loading device. While pulling the pipe jacking replacement section, synchronously jack the pipe joints from the second to the Nth pipe joint into the first pipe joint through the rectangular hole on the first side of the model box in sequence.

[0028] S8: Synchronously export the monitoring data, and subtract the frictional force obtained in S3 to get the stress - strain curve.

[0029] The beneficial effects of the present invention compared with the prior art are as follows: The rectangular pipe jacking model test device proposed by the present invention can carry out model tests on pipe jacking under complex conditions indoors. This test device simplifies and demonstrates the excavation process, replaces the unloaded soil body, and realizes visual processing and dynamic monitoring of the surface settlement, pipe - soil contact and slurry diffusion conditions throughout the test. Specifically, it has at least one or more of the following actual effects:

[0030] The detachable box panels of the model box are simply assembled, and can be assembled by inserting and pulling up and down. Rectangular holes with specified sizes and numbers can be set at specified positions. By replacing the detachable box panels, pipe jacking model tests under different burial depths, different sizes, different shapes, different numbers, etc. can be realized.

[0031] The pipe jacking replacement section is used to replace the original soil body in this part. By changing its external friction coefficient, it equivalently replaces the effects of the internal friction angle and cohesion of the soil body; by adding weight inside the pipe jacking replacement section, it equivalently replaces the self - weight stress of the original soil body at this depth; by applying pushing and pulling forces to it through the front loading device, it equivalently replaces the head - on resistance during pipe jacking.

[0032] The pipe jacking replacement section forms a rectangular pipe jacking model with the smallest tunneling size through the splicing of conventional splicing sections; different tunneling size rectangular pipe jacking models are realized by inserting free splicing sections between two adjacent conventional splicing sections on two opposite faces or four opposite faces of the rectangular pipe jacking model formed by the splicing of conventional splicing sections. By adjusting the size of the rectangular hole, pipe jacking construction with different tunneling sizes can be simulated.

[0033] The model box uses a transparent lidless box body, and is used in conjunction with a transparent pipe jacking replacement section and filled with transparent test soil to achieve visualization throughout the test, and to display in real time the surface settlement, pipe-soil contact, slurry diffusion, etc.

[0034] The loading device changes the traditional "jacking" method of pipe jacking model tests using a rear jack, and instead uses a "pulling" method set in the front, eliminating the manual discharge process of the excavated soil in traditional pipe jacking model tests, and at the same time avoiding the compression of the soil in front of the excavation face during the jacking of the model test; the push-pull pipe jacking replacement section can not only control the face resistance, but also directly "pull out" the excavated soil.

[0035] It should be understood that the implementation of any embodiment of the present invention does not mean that multiple or all of the above beneficial effects need to be simultaneously achieved or reached. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained according to the provided drawings.

[0037] The structures, ratios, sizes, etc. shown in this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have technical substance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

[0038] Figure 1 Overall schematic diagram of the test device for an embodiment of the present invention (before loading);

[0039] Figure 2 Schematic diagram of the structure of the model box for an embodiment of the present invention;

[0040] Figure 3 Schematic diagram of the structure of the model box for an embodiment of the present invention (before assembly);

[0041] Figure 4 Schematic diagram of the splicing structure of the pipe jacking replacement section for an embodiment of the present invention;

[0042] Figure 5 Schematic diagram of the structure of the loading device for an embodiment of the present invention;

[0043] Figure 6Schematic diagram of the sliding frame structure according to an embodiment of the present invention;

[0044] Figure 7 Schematic diagram of the sliding block and guide rail structures according to an embodiment of the present invention;

[0045] Figure 8 Overall schematic diagram of the test device according to an embodiment of the present invention (after loading). Detailed implementation manners

[0046] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer and more understandable, the embodiments of the present invention will be further described in detail below in conjunction with the embodiments and the drawings. Herein, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but not to limit the present invention.

[0047] In the present invention, unless otherwise clearly defined and limited, terms such as "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] It should be understood that terms such as "including / containing", "consisting of..." or any other variant are intended to cover non-exclusive inclusion, so that a product, device, process or method including a series of elements not only includes those elements, but also includes other elements that are not explicitly listed when necessary, or also includes elements inherent to such product, device, process or method. Without further limitation, elements defined by the statement "including / containing...", "consisting of..." do not exclude the existence of additional identical elements in the product, device, process or method including the said elements.

[0049] It is also necessary to understand that terms such as "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and cannot be understood as a limitation to the present invention.

[0050] In addition, terms such as "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0051] At present, there are problems in the indoor model test of rectangular pipe jacking, such as the excavation process is difficult to reproduce, the unloaded soil is difficult to discharge, and the pipe-soil contact and slurry diffusion are difficult to display. The existence of these problems makes the existing rectangular pipe jacking model test unable to accurately describe the engineering process, and there is also a large deviation between the theoretical prediction and the on-site measurement.

[0052] Based on this, the present invention proposes a new rectangular pipe jacking model test device. This rectangular pipe jacking model test device can carry out model tests of pipe jacking under complex conditions indoors. The rectangular pipe jacking model test device uses a pipe jacking replacement section to replace the soil body in front of the excavation face, and uses a push-pull pipe jacking replacement section to replace the jacking of the pipe jacking pipe section by a jack, thereby simplifying the excavation process, omitting the process of discharging the unloaded soil body, and realizing visual processing and dynamic monitoring of the surface settlement, pipe-soil contact and slurry diffusion conditions throughout the test.

[0053] The implementation of the present invention will be described in detail below in conjunction with the preferred embodiments.

[0054] As Figure 1 shown, the present invention proposes a rectangular pipe jacking model test device, including: a model box 1, a pipe jacking replacement section 2, a pipe jacking pipe section 3 and a loading device.

[0055] Specifically, the model box 1 is used to load the test soil body, and rectangular holes 103 are correspondingly opened on the opposite first side and second side thereof, as Figure 2 , Figure 3 shown.

[0056] The pipe jacking replacement section 2 is partially or entirely inserted into the model box 1 through the rectangular hole 103 on the second side of the model box 1, and is used to simulate the process of the pipe jacking machine excavating and discharging the excavated soil body.

[0057] In specific implementation, the pipe jacking replacement section 2 equivalently replaces the action of the internal friction angle and cohesion of the soil body by changing its external friction coefficient. The pipe jacking replacement section 2 equivalently replaces the self-weight stress of the original soil body at this depth by adding weight inside it. The pipe jacking replacement section 2 equivalently replaces the head-on resistance during the jacking of the pipe jacking pipe section 3 by the pushing and pulling force applied to it by the front loading device.

[0058] The pipe jacking pipe section 3 includes a first pipe section and pipe sections two to N, and the first pipe section is connected to the end of the pipe jacking replacement section 2.

[0059] The loading device is arranged in front of the pipe jacking replacement section 2 and is used to pull the pipe jacking replacement section 2. During the pulling process, the pipe sections two to N are synchronously jacked into the first pipe section in sequence from the rectangular hole 103 on the first side of the model box 1.

[0060] In the present invention, the rectangular pipe-jacking model test device replaces the soil mass in front of the excavation face with the pipe-jacking replacement section 2, and uses the loading device to push and pull the pipe-jacking replacement section 2 to replace the jacking of the pipe-jacking pipe section 3, which simplifies the excavation process and omits the process of discharging and unloading the soil mass.

[0061] In some embodiments, the model box 1 is a transparent lidless box. Preferably, the test soil mass is a transparent soil mass. The present invention visually presents the ground settlement situation through the model box 1 and the test soil mass, realizing the visualization of the whole test process.

[0062] In some embodiments, referring to Figure 2 、 Figure 3 , the model box 1 includes the left and right side box plates, the front and rear side box plates that form the surrounding panels of the box body, and the bottom box plate that connects the surrounding box plates. Among them, the left and right side box plates and the bottom box plate are connected to form the non-detachable box plate 101, and the front and rear side box plates are used as the detachable box plate 102 and are movably inserted into the non-detachable box plate 101, or the front and rear side box plates and the bottom box plate are connected to form the non-detachable box plate 101, and the left and right side box plates are used as the detachable box plate 102 and are movably inserted into the non-detachable box plate 101. Slots are correspondingly formed on the non-detachable box plate 101.

[0063] In some embodiments, the first side and the second side that are opposite to each other of the model box 1 are detachable box plates 102, and rectangular holes 103 are formed on the detachable box plates 102.

[0064] It should be understood that the first side and the second side of the model box 1 mentioned here correspond to the jacking direction of the pipe-jacking pipe section 3. The side where the pipe-jacking pipe section 3 first jacks into along the rectangular hole 103 of the model box 1 is the first side, and the side where it jacks in later is the second side, which can be the left and right side box plates or the front and rear side box plates of the model box 1.

[0065] Continuing to refer to Figure 2 、 Figure 3 , the present invention preferably takes the front and rear side box plates as the first side and the second side of the model box 1, the left and right side box plates and the bottom box plate are connected to form the non-detachable box plate 101, and the front and rear side box plates are used as the detachable box plate 102 and are movably inserted into the non-detachable box plate 101.

[0066] In the present invention, the model box 1 is simply assembled. The detachable box plate 102 can be assembled by simply inserting it up and down. The detachable box plate 102 can be provided with rectangular holes 103 of specified dimensions and specified quantities at specified positions. By replacing the detachable box plate 102, pipe-jacking model tests under different burial depths, different dimensions, different shapes, different quantities, etc. can be realized.

[0067] Preferably, the non-detachable box board 101 of the model box 1 is made of high-strength and high-hardness tempered glass, and the detachable box board 102 is an acrylic board with rectangular holes 103 of specified dimensions set at specified positions in advance. The density of acrylic is 1.2 g / cm 3 , and that of tempered glass is 2.6 g / cm 3 . For easy disassembly, the detachable box board 102 is made of the lighter acrylic material; for being able to withstand the self-weight stress of the soil mass and the lateral earth pressure sufficiently, the non-detachable box board 101 is made of tempered glass with higher strength.

[0068] During specific implementation, a hollow rectangular hole 103 of specified dimensions is opened at a specified depth of the detachable box board 102 in advance to simulate the jacking pipe opening; the installation and disassembly of the detachable box board 102 are realized by inserting and pulling out the detachable box board 102 up and down into the card slot of the non-detachable box board 101. Preferably, a plurality of detachable box boards 102 are provided according to the different dimensions of the hollow rectangular holes 103 opened in the middle thereof, and the jacking pipe model tests under different burial depths, different dimensions, different shapes, different quantities and other conditions are realized by replacing different detachable box boards 102.

[0069] In the present invention, the dimensions of the model box 1, and the thicknesses of the non-detachable box board 101 and the detachable box board 102 are all determined by the designed model test conditions. Generally, the thickness of the detachable box board 102 is not greater than that of the non-detachable box board 101. Preferably, the thickness of the detachable box board 102 is not greater than 80% of the thickness of the non-detachable box board 101.

[0070] In some embodiments, referring to Figure 4 , the jacking pipe replacement section 2 includes four conventional splicing sections 201, and the four conventional splicing sections 201 are spliced with each other to form a rectangular jacking pipe model with the minimum tunneling size.

[0071] Preferably, the cross sections of the four conventional splicing sections 201 are L-shaped, and the four L-shaped conventional splicing sections form the four corners of the rectangular jacking pipe model.

[0072] Preferably, the shapes and dimensions of the four conventional splicing sections 201 should be exactly the same, which is convenient for the unified processing and rapid assembly of the conventional splicing sections 201.

[0073] Preferably, the conventional splicing section 201 is made of acrylic material, which is convenient for presenting the pipe-soil contact visually in real time.

[0074] In some embodiments, still referring to Figure 4 , the jacking pipe replacement section 2 further includes at least one free splicing section 202 arranged between two adjacent conventional splicing sections 201, and the free splicing section 202 is symmetrically arranged on at least two opposite faces of the rectangular jacking pipe model. The conventional splicing section 201 and the free splicing section 202 are spliced with each other to form a rectangular jacking pipe model with a predetermined tunneling size.

[0075] In the present invention, by adding a freely spliced section 202, the dimensions of the rectangular pipe-jacking model can be changed horizontally and vertically along the pipe-jacking replacement section 2.

[0076] The pipe-jacking replacement section 2 realizes a rectangular pipe-jacking model with the minimum tunneling size through splicing of the conventional splicing sections 201, and realizes a rectangular pipe-jacking model with different tunneling sizes by inserting the freely spliced sections 202 between at least two adjacent conventional splicing sections 201 on two opposite faces of the rectangular pipe-jacking model formed by splicing the conventional splicing sections 201.

[0077] It should be understood that the same number of freely spliced sections 202 are added between two adjacent conventional splicing sections 201 on the left and right opposite faces or the upper and lower opposite faces. For example, one, two or more freely spliced sections 202 can be inserted, which is specifically determined by the predetermined tunneling size in the actual simulation. See Figure 4 , preferably, in the present invention, one freely spliced section 202 is inserted between two adjacent conventional splicing sections 201 in the upper, lower, left and right directions of the rectangular pipe-jacking model formed by splicing the conventional splicing sections 201 to obtain a pipe-jacking replacement section 2 with a square cross-section.

[0078] It should be understood that the shape and size of each freely spliced section 202 should be exactly the same, and the conventional splicing section 201 and the freely spliced section 202 are of equal length in the jacking direction and not less than the total length of the model box 1, that is, not less than the distance between the opposite first side and the second side.

[0079] Preferably, the freely spliced section 202 is made of acrylic material, which is convenient for intuitively presenting the pipe-soil contact in real time.

[0080] In the present invention, the conventional splicing section 201 and the freely spliced section 202 replace the original soil body in this part, and the process of discharging and unloading the soil body is omitted.

[0081] In some embodiments, continuing to refer to Figure 4 , the splicing method of the conventional splicing section 201 and the freely spliced section 202 is slot splicing. Grooves and / or teeth are respectively provided at the splicing joints on both sides of the conventional splicing section 201 and the freely spliced section 202, and the grooves and teeth are evenly distributed along the splicing joint.

[0082] It should be understood that both sides of each conventional splicing section 201 can be grooves or teeth, or one side can be a groove and the other side can be a tooth, as long as it can ensure groove-tooth splicing with the adjacent conventional splicing section 201 or freely spliced section 202.

[0083] Preferably, one side of the splicing joint of the conventional splicing section 201 is set as a groove and the other side is set as a tooth. Similarly, one side of the left and right splicing joints of the freely spliced section 202 is set as a groove and the other side is set as a tooth.

[0084] During specific splicing, when the pipe jacking replacement section 2 forms a rectangular pipe jacking model with the minimum tunneling size only through the splicing of four conventional splicing sections 201, the teeth of each conventional splicing section 201 are spliced with the grooves of the opposite conventional splicing section 201, and the grooves and teeth of the four conventional splicing sections 201 are sequentially spliced with each other to form the four corners of the rectangular pipe jacking model. When the pipe jacking replacement section 2 forms a rectangular pipe jacking model with a predetermined tunneling size through the splicing of four conventional splicing sections 201 and at least two free splicing sections 202, the teeth of each conventional splicing section 201 are spliced with the grooves of the opposite conventional splicing section 201 or the grooves of the free splicing section 202, or the grooves of each conventional splicing section 201 are spliced with the teeth of the opposite conventional splicing section 201 or the teeth of the free splicing section 202.

[0085] Preferably, referring further to Figure 4 , the conventional splicing sections 201 and the free splicing sections 202 are arranged along the four orientations of the upper, lower, left, and right of the pipe jacking replacement section 2. The reason for not arranging them along the front and rear orientations of the pipe jacking replacement section 2 is to prevent the splicing sections from being loaded during the test, resulting in the separation of the grooves and teeth.

[0086] It should be understood that the front and rear orientations here are relative to the jacking direction of the pipe jacking pipe section 3. The jacking direction of the pipe jacking pipe section 3 is the front orientation, and the reverse jacking direction is the rear orientation.

[0087] In some embodiments, the loading device includes a support platform 4, a sliding frame 5, and a jacking mechanism 6.

[0088] Referring to Figure 1 and Figures 5 - 7 , the support platform 4 is arranged in front of the rectangular hole 103 on the second side of the model box 1. The sliding frame 5 is connected to the pipe jacking replacement section 2 and can slide back and forth on the support platform 4 under the jacking action of the jacking mechanism 6 to pull the pipe jacking replacement section 2.

[0089] Guide rails 401 are arranged on both sides of the support platform 4 along the jacking direction for the sliding frame 5 to slide on the support platform 4. The sliding frame 5 includes a force application rod 501 connected to the pipe jacking replacement section 2, a sliding block 502 connected to the force application rod 501 and cooperating with the guide rail 401 for sliding, and a force application frame 503 for the jacking mechanism 6 to push and pull.

[0090] The jacking mechanism 6 includes a reaction frame 601 and an oil cylinder 602. The oil cylinder 602 is arranged on the reaction frame 601. The reaction frame 601 drives the pipe jacking replacement section 2 to move on the guide rail 401 by pushing and pulling the force application frame 503 through the oil cylinder 602.

[0091] Specifically, the support platform 4 is arranged in front of the pipe jacking replacement section 2 for placing the pulled pipe jacking replacement section 2. The guide rails 401 are located at the upper two edges of the support platform 4. The sliding blocks 502 cooperate with the guide rails 401 and move along the direction of the guide rails 401. The force application rod 501 is connected to the pipe jacking replacement section 2 and is also connected to the sliding blocks 502. One end of the oil cylinder 602 is fixed on the reaction frame 601, and the other end corresponds to the force application frame 503.

[0092] In the present invention, the pushing and pulling of the pipe jacking replacement section 2 are realized by controlling the displacement parameter of the sliding block 502 on the guide rail 401. The design of the sliding block 502 and the guide rail 401 can ensure that the direction of the axial force application is the same as the jacking direction of the pipe jacking pipe section 3, without generating bending moment or torque. The guide rail 401 can be a chute formed on the two edges of the support platform 4. The sliding block 502 is clamped on the chute and is connected and fixed to the force application frame 503 through bolts, which is convenient for installation and disassembly.

[0093] In the present invention, the oil cylinder 602 pushes the force application frame 503 along the jacking direction of the pipe jacking pipe section 3, and then pulls the pipe jacking replacement section 2. The pipe jacking replacement section 2 is pulled along the guide rail 401 on the support platform 4 in the jacking direction through the sliding block 502 connected by the force application rod 501.

[0094] It should be understood that the force application rod 501 only applies axial force to the pipe jacking replacement section 2, so it is not strictly required that the acting point is set in the middle of the pipe jacking replacement section 2. Preferably, the acting point where the force application rod 501 applies axial force to the pipe jacking replacement section 2 can be set on the conventional splicing section 201 at the lower part of the front end of the pipe jacking replacement section 2. In this way, when the free splicing section 202 is increased in the transverse and / or longitudinal directions of the pipe jacking replacement section 2, the position of the acting point will not change, and the operation is more convenient.

[0095] The connection between the force application rod 501 and the pipe jacking replacement section 2 can be that connection rings are symmetrically arranged on the conventional splicing section 201 at the lower part of the front end of the pipe jacking replacement section 2, and the force application rod 501 passes through the connection rings to be connected to the pipe jacking replacement section 2. Or connection holes 203 are symmetrically arranged on the conventional splicing section 201 at the lower part of the front end of the pipe jacking replacement section 2, and the force application rod 501 passes through the connection holes 203 to be connected to the pipe jacking replacement section 2. The specific connection form between the force application rod 501 and the pipe jacking replacement section 2 is not limited in the present invention, as long as it satisfies that the force application rod 501 can pull the pipe jacking replacement section 2 along the jacking direction of the pipe jacking pipe section 3.

[0096] Preferably, the force application rod 501 is connected to the monitoring equipment required for the test. The pipe jacking replacement section 2 is pulled along the guide rail 401 on the support platform 4 in the jacking direction through the sliding block 502 connected by the force application rod 501. During the pulling process, the monitoring equipment collects and generates the required data graph in real time.

[0097] It should be understood that the length of the pipe-jacking replacement section 2 should not be less than the length of the model box 1, so as to facilitate the replacement of the original soil in this part. After the pipe-jacking replacement section 2 completely penetrates the model box 1, there should still be a remainder on one side of the rectangular hole 103 on the second side of the model box 1, which is convenient for connecting with the force-applying rod 501.

[0098] Preferably, the length of the guide rail 401 should not be less than the length of the pipe-jacking replacement section 2 to ensure that the pipe-jacking replacement section 2 can be completely pulled out; the length of the force-applying rod 501 should be determined by the distance between the guide rails 401.

[0099] Preferably, the support platform 4 is a test table or a test bench.

[0100] Preferably, the support platform 4 is a telescopic and liftable support platform. The support platform 4 can adjust its height in the vertical direction to facilitate adapting to different model boxes and the heights of the experimental tables, and can also adjust its length in the horizontal direction to facilitate adapting to different model boxes and the widths of the experimental tables.

[0101] The support platform 4 is arranged in front of the rectangular hole 103 on the second side of the model box 1 along the jacking direction of the pipe-jacking pipe section 3. During the test, the height of the support platform 4 is adjusted in the vertical direction so that the upper surface of the support platform 4 is in contact with the lower surface of the pipe-jacking replacement section 2 to facilitate the conduct of the test. The length of the support platform 4 is adjusted in the horizontal direction so that the length of the support platform 4 is not less than the length of the pipe-jacking replacement section 2, which is convenient for completely placing the pulled pipe-jacking replacement section 2.

[0102] During specific implementation, the rear of the support platform 4 is closely attached to the front of the rectangular hole 103 on the second side of the model box 1. By adjusting the support platform 4, the lower surface of the pipe-jacking replacement section 2 is completely attached to the upper surface of the support platform 4. The front end of the pipe-jacking replacement section 2 is connected to the force-applying rod 501. The force-applying rod 501 is connected to the sliding block 502 and the force-applying frame 503. The force-applying frame 503 corresponds to the oil cylinder 602. The oil cylinder 602 pushes the force-applying frame 503 along the jacking direction, and then the pipe-jacking replacement section 2 connected to the force-applying rod 501 is pulled. The pipe-jacking replacement section 2 is pulled forward along the guide rail 401 on the support platform 4 through the sliding block 502 connected to the force-applying rod 501. During the pulling process, the pipe sections from the second to the Nth pipe section are synchronously jacked into the pipe section 1 in sequence from the rectangular hole 103 on the first side of the model box 1.

[0103] In the present invention, the oil cylinder 602 controls the magnitude and direction of the loading force through a computer.

[0104] Preferably, two groups of guide rails 401 are provided, symmetrically arranged on both sides of the upper surface of the support platform 4 along the jacking direction. The sliding blocks 502 are symmetrically arranged on the two groups of guide rails 401. The two ends of the force-applying rod 501 are connected to the two sliding blocks 502 at the upper part of the support platform 4, and the middle is connected to the front end of the pipe-jacking replacement section 2. The two ends of the force-applying frame 503 are connected to the two sliding blocks 502 at the lower part of the support platform 4.

[0105] The symmetrically arranged guide rails 401 can make the overall force on the pipe jacking replacement section 2 pulled by the force application rod 501 connected to the sliding block 502 along the direction of the guide rail 401 more uniform, and the pipe jacking replacement section 2 can stably pull forward along the jacking direction of the pipe jacking pipe section 3 without deviation.

[0106] See Figure 5 , the reaction frame 601 is arranged across the support platform 4, a cross beam 603 is slidably connected between the two legs of the reaction frame 601, the cross beam 603 is arranged below the support platform 4, and the oil cylinder 602 is fixed on the cross beam 603. By adjusting the position of the cross beam 603, the oil cylinder 602 is aligned with the force application frame 503 to facilitate pushing the pipe jacking replacement section 2 along the jacking direction.

[0107] Preferably, the reaction frame 601 is provided with a plurality of bolt holes along its height direction, and the two ends of the cross beam 603 are correspondingly provided with bolt holes. The cross beam 603 is bolted between the reaction frames 601 according to the required height.

[0108] The rectangular pipe jacking model test device proposed by the present invention can accurately describe the engineering process. The soil in front of the excavation face is replaced by the pipe jacking replacement section, and the pipe jacking replacement section is pushed and pulled by the loading device instead of the jack to jack the pipe jacking pipe section, which simplifies and presents the excavation process, omits the process of discharging and unloading the soil, and at the same time, the surface settlement, pipe-soil contact, and slurry diffusion conditions can be visually presented in real time by using the transparent uncovered box body, transparent soil, and acrylic pipe jacking replacement section.

[0109] The present invention also proposes a test method based on the above rectangular pipe jacking model test device. This test method can easily reproduce the excavation process, guide the use of this rectangular pipe jacking model test device to carry out a complete model test, and solve the problems such as the difficulty of discharging the unloaded soil, the difficulty of presenting the pipe-soil contact and slurry diffusion in the existing indoor model test of rectangular pipe jacking. Specifically, it includes:

[0110] S1: According to the pipe jacking pipe section dimensions, burial depths, and quantities set in the test plan, select the model box 1 corresponding to the rectangular hole 103 and splice the corresponding pipe jacking replacement section 2;

[0111] S2: According to the soil parameters set in the test plan, set them on the pipe jacking replacement section according to the test similarity ratio to simulate the original soil mass;

[0112] Specifically in implementation, the set soil parameters include soil unit weight, shear strength, tensile strength, cohesion, etc., and are set on the pipe jacking replacement section according to the test similarity ratio;

[0113] S3: Pull the pipe jacking replacement section 2 on the support platform 4 in advance through the loading device, measure the dynamic friction coefficient between the pipe jacking replacement section 2 and the support platform 4 at this time, and then obtain the relationship curve between the extension length of the pipe jacking replacement section 2 and the frictional force.

[0114] S4: Fill the test soil in the model box 1 and complete the relevant pre - monitoring preparation work according to the test plan.

[0115] S5: When the test soil is filled to the elevation of the pipe jacking replacement section 2, the pipe jacking replacement section 2 passes through the rectangular holes 103 on the second side and the first side of the model box 1 in sequence, and is integrally inserted into the model box 1, and then continue to fill the test soil until the specified elevation.

[0116] S6: Connect the first pipe joint to the end of the pipe jacking replacement section 2, and complete the relevant pre - monitoring preparation work by selecting the monitoring method according to the test plan.

[0117] Specifically, when implementing, the relevant pre - monitoring preparation work includes: calibrating the monitoring points, pasting strain gauges, debugging the monitoring display mode, etc.

[0118] S7: Start the loading device, pull the pipe jacking replacement section 2, and simultaneously jack the second pipe joint to the Nth pipe joint into the first pipe joint synchronously from the rectangular hole 103 at the first end of the model box 1, as Figure 8 shown;

[0119] S8: Synchronously export the relevant monitoring data and stress - strain curves.

[0120] Specifically, when processing the stress - strain curve, the frictional force obtained in S3 should be subtracted.

[0121] It is easy for those skilled in the art to understand that, on the premise of no conflict, the above - mentioned preferred solutions can be freely combined and superimposed.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A rectangular pipe jacking model test device, characterized in that, Comprising: A model box for loading test soil mass, and rectangular holes are correspondingly formed in the opposite first side and second side thereof; the model box is a transparent lidless box body, and the first side and the second side are detachable box plates, on which the rectangular holes are formed; A jacking pipe replacement section which is partially or wholly inserted into the model box through the rectangular hole on the second side of the model box and is used for simulating the process of the jacking machine excavating and discharging the excavated soil mass; Jacking pipe segments, including pipe segment one and pipe segments two to N, wherein the pipe segment one is connected to the end of the jacking pipe replacement section; A loading device arranged in front of the jacking pipe replacement section for pulling the jacking pipe replacement section, and during the pulling process, the pipe segments two to N are synchronously jacked into the pipe segment one in sequence from the rectangular hole on the first side of the model box.

2. The rectangular pipe-jacking model test device according to claim 1, characterized in that The jacking pipe replacement section comprises four conventional splicing sections, and the four conventional splicing sections are spliced with each other to form a rectangular jacking pipe model with the minimum tunneling size.

3. The rectangular pipe-jacking model test device according to claim 2, characterized in that The cross sections of the four conventional splicing sections are L-shaped, and the four L-shaped conventional splicing sections form the four corners of the rectangular jacking pipe model.

4. The rectangular pipe jacking model test device according to claim 2, characterized in that, The jacking pipe replacement section further comprises at least one free splicing section arranged between two adjacent conventional splicing sections, and the free splicing section is symmetrically arranged on at least two opposite faces of the rectangular jacking pipe model. The conventional splicing section and the free splicing section are spliced with each other to form a rectangular jacking pipe model with a predetermined tunneling size.

5. The rectangular pipe-jacking model test device according to claim 4, wherein, The splicing mode of the conventional splicing section and the free splicing section is slot splicing, and grooves and / or teeth are respectively arranged at the splicing positions of the two side edges of the conventional splicing section and the free splicing section.

6. The rectangular pipe-jacking model test device according to claim 1, wherein, The loading device comprises a support platform, a sliding frame and a jacking mechanism. The support platform is arranged in front of the rectangular hole on the second side of the model box. The sliding frame is connected to the jacking pipe replacement section and can slide back and forth on the support platform under the jacking action of the jacking mechanism to pull the jacking pipe replacement section.

7. The rectangular pipe jacking model test device according to claim 6, characterized in that, Guide rails are arranged on both sides of the support platform along the jacking direction; the sliding frame comprises a force application rod connected to the jacking pipe replacement section, sliding blocks connected to both ends of the force application rod and cooperating with the guide rails on both sides, and a force application frame connected to the sliding blocks on both sides. The force application frame is arranged below the support platform.

8. The rectangular pipe jacking model test device according to claim 7, wherein The jacking mechanism comprises a reaction frame and an oil cylinder. The reaction frame is arranged across both sides of the support platform, and the oil cylinder is arranged on the reaction frame. The force application frame is pushed and pulled by the oil cylinder to drive the jacking pipe replacement section to move along the guide rail.

9. A rectangular pipe jacking model test method based on the rectangular pipe jacking model test device according to any one of claims 1 to 8, characterized in that, Comprising the following steps: S1: According to the sizes, burial depths and quantities of the jacking pipe segments set in the test scheme, select a model box corresponding to the rectangular hole and splice the corresponding jacking pipe replacement section; S2: According to the soil mass parameters in the test scheme, set the test similarity ratio on the jacking pipe replacement section to simulate the original soil mass; S3: Pull the jacking pipe replacement section on the support platform in advance, measure the dynamic friction coefficient between the jacking pipe replacement section and the support platform, and obtain the relationship curve between the extended length of the jacking pipe replacement section and the frictional force; S4: Fill the test soil mass into the model box and complete the relevant pre-monitoring preparation work according to the test scheme; S5: When the test soil body is filled to the bottom elevation of the pipe jacking replacement section, the pipe jacking replacement section is successively passed through the rectangular holes on the second side and the first side of the model box and integrally inserted into the model box, and then the test soil body is continuously filled until the specified elevation; S6: Connect the first pipe joint to the end of the pipe jacking replacement section and complete the relevant pre - monitoring preparation work according to the test plan; S7: Start the loading device, pull the pipe jacking replacement section and simultaneously jack the second pipe joint to the Nth pipe joint into the first pipe joint from the rectangular hole on the first side of the model box; S8: Synchronously export the monitoring data and subtract the frictional force obtained in S3 to obtain the stress - strain curve.

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