Indoor test simulation system and method for rectangular pipe jacking curve construction

Abstract

The invention discloses an indoor test simulation system and method for rectangular pipe jacking curve construction, and relates to the technical field of pipe jacking construction tests. Comprising a model box, a pushing platform mechanism, a pipe jacking mechanism, a soil body cutting device, an auger unearthing mechanism and a multi-pipe grouting system, a reserved pipe hole is formed in the side wall of a box body of the model box, the pushing platform mechanism is located on the side, provided with the reserved pipe hole, of the model box, and the pushing platform mechanism comprises a supporting rack and a pipe jacking sliding rail device; the pipe jacking mechanism comprises a rectangular jacking pipe, a jacking mechanism and deviation rectifying mechanisms located on the left side and the right side of the jacking pipe, the jacking pipe is placed on the jacking pipe sliding rail device, the front end of the jacking pipe penetrates through the reserved pipe hole and is buried in the model box, and the rear end of the jacking pipe is connected with the jacking mechanism; the auger unearthing mechanism is used for conveying the cut soil out of the model box, and the multi-pipe grouting system is used for simulating real-time grouting. The system can better simulate the disturbance of the rectangular jacking pipe to the surrounding soil body in the curve construction process.

Description

Technical Field

[0001] The invention relates to the technical field of pipe jacking construction tests, and in particular to an indoor test simulation system and method for rectangular pipe jacking curve construction. Background Art

[0002] As the construction section of municipal tunnels gradually develops towards larger sections, large-section rectangular pipe jacking machines are widely used in development. Compared with circular tunnels, rectangular tunnels can increase space utilization by about 20% and are widely used in urban integrated pipe corridors, pedestrian crossings, highways and subway tunnels. Due to their poor excavation arching effect, rectangular tunnels are usually constructed by open-cut method. However, with the increasingly harsh urban construction environment and the advancement of pipe jacking technology, more and more rectangular tunnels are beginning to use pipe jacking construction, and the jacking section is getting larger and the distance is getting longer. Due to the characteristics of its shape, the excavation face stability of large-section rectangular tunnels is poor during the jacking process. If the support pressure is not set properly, instability is likely to occur, resulting in surface collapse, damage to surrounding buildings and other consequences. Therefore, studying the excavation face stability of large-section rectangular pipe jacking provides theoretical guidance for the setting of support pressure, which is of great significance for ensuring the safe implementation of the project.

[0003] At present, the existing pipe jacking model test devices all have a fixed jacking depth, and the simulation situation is relatively simple. For example, the Chinese patent application number is 201920103759.0, "An indoor test simulation system for pipe jacking construction". The pipe jacking machine in this patent test simulation system is a circular cross-section pipe segment. At the same time, its pipe section can only be jacked horizontally along a linear guide rail, and its unloaded soil is difficult to discharge. Summary of the invention

[0004] The purpose of the present invention is to provide an indoor test simulation system and method for rectangular pipe jacking curve construction to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an indoor test simulation system for rectangular pipe jacking curve construction, comprising a model box, a jacking platform mechanism, a pipe jacking mechanism, a soil cutting device, a dragon excavation mechanism and a multi-tube grouting system; the model box comprises a box body with an open top, and a reserved pipe hole is formed on the side wall of the box body; the jacking platform mechanism is located on a side of the model box with the reserved pipe hole, and the jacking platform mechanism comprises a supporting frame and a pipe jacking slide rail device installed on the supporting frame; the pipe jacking mechanism comprises a pipe jacking, a jacking machine The jacking pipe is a square pipe, and along the circumferential direction of the axis of the square pipe, each adjacent two side surfaces have a smooth transition; the jacking pipe is placed on the jacking pipe slide rail device, and the front end passes through the reserved pipe hole and is buried in the model box, the rear end of the jacking pipe is connected with the jacking mechanism, and the correcting mechanism is arranged on the left and right sides of the jacking pipe; the soil cutting device is built in the jacking pipe; the Jiaolong excavation mechanism is used for transporting the soil cut by the soil cutting device to the outside of the model box; the multi-tube grouting system is used for simulating real-time grouting.

[0006] Based on the above technical features, the present invention pushes the jacking pipe through the jacking mechanism so that the jacking pipe can move along its own axial direction, and corrects the jacking pipe to the left or right during the jacking process through the correction mechanism arranged on both sides of the jacking pipe, so that the jacking pipe deviates to the left or right during the jacking process, thereby satisfying the jacking pipe to perform curved jacking in the model box along the jacking pipe slide rail device, breaking the problem that the existing jacking pipe model test device can only simulate the construction process of straight jacking along a fixed route, and the simulation situation is relatively single; at the same time, the soil cut by the soil cutting device can be cleaned and discharged to the outside of the model box in time through the Jiaolong excavation mechanism, solving the problem that the unloaded soil is difficult to discharge.

[0007] Preferably in the present technical solution, the jacking mechanism comprises a jacking support, a jacking cylinder and a hydraulic station, wherein the jacking support is fixedly connected to the rear end of the jacking pipe, the jacking cylinder is connected to the jacking support, and the hydraulic station is used to provide pressure oil to the jacking cylinder.

[0008] Based on the above technical features, the jacking pipe is pushed in by using a power system consisting of a jacking cylinder and a hydraulic station with high control accuracy. By controlling the flow of pressure oil delivered to the jacking cylinder by the hydraulic station, the pressure can be better and more accurately controlled, which is more suitable for the straight and curved jacking construction process of the jacking pipe model test device of the present invention.

[0009] Preferably in the present technical solution, the soil cutting device comprises a cutter disc, a first transmission shaft and a cutter disc driving device, wherein the cutter disc is arranged at the front end of the top pipe, and the cutter disc is connected to the cutter disc driving device through the first transmission shaft, and the cutter disc driving device can drive the cutter disc to rotate and cut the soil; more preferably, the cutter disc comprises an intermediate top cutter, a gear box, a first gear, a peripheral top cutter, a second gear and a rack; the intermediate top cutter is rigidly coaxially mounted on the end of the first transmission shaft; the gear box is composed of two guard plates, both of which are sleeved on the first transmission shaft, and the two guard plates are fixed to the inner wall of the top pipe, and a accommodating space is formed between the two guard plates; the first gear is located in the accommodating space, and the first gear is rigidly coaxially connected to the first transmission shaft; the peripheral top cutter is rotatably connected to the gear box through the second transmission shaft, and the axis of the second transmission shaft is parallel to the axis of the first transmission shaft; the second gear is located in the accommodating space, and the second gear is rigidly coaxially connected to the second transmission shaft, and the second gear and the first gear are connected through the rack transmission.

[0010] Based on the above technical features, the cutterhead in the present invention specifically includes a middle top cutter and four peripheral top cutters arranged at the end angle positions, so that the effective cutting area of ​​the cutterhead can reach between 80% and 90%, further reducing the pressure on the face of the tunnel. At the same time, the excavation surface formed by cutting and excavating by its soil cutting device is rectangular, which is suitable for the curved construction process of the rectangular jacking pipe of the present invention, and provides theoretical guidance for studying the stability of the excavation surface of the large-section rectangular jacking pipe and setting the support pressure.

[0011] Preferably in the present technical solution, a plurality of grouting holes are opened on the side walls around the top pipe along the axial direction of the top pipe; the multi-tube grouting system includes a grouting station, a main slurry outlet pipe, a connector and an auxiliary slurry outlet pipe, the grouting station is equipped with slurry, one end of the main slurry outlet pipe is connected to the grouting station, and the other end of the main slurry outlet pipe is connected to the auxiliary slurry outlet pipe through a connector, the number of the auxiliary slurry outlet pipes is adapted to the number of the grouting holes, and the auxiliary slurry outlet pipes are connected to the grouting holes.

[0012] Preferably in the present technical solution, the jacking pipe slide rail device comprises a groove rail, a slide rail and a roller; a side of the groove rail different from the groove notch is fixed to the support frame; the slide rail is respectively fixed to both sides of the groove and the bottom of the groove of the groove rail; along the axial direction of the slide rail, the roller is rotatably connected to the slide rail, the jacking pipe is located in the groove of the groove rail, and the outer wall of the jacking pipe is in contact with the roller.

[0013] Preferably in the present technical solution, the correcting mechanism includes a limit baffle, a correcting bolt and a locking nut, the lower part of the limit baffle is fixed to the supporting frame, the screw rod of the correcting bolt passes through the limit baffle and the locking nut in sequence, and the end face of the correcting bolt is against the side wall of the groove of the groove track.

[0014] Preferably in the present technical solution, the indoor test simulation system also includes an earth press and a stress sheet; the earth press is arranged in multiple layers in the test soil of the model box, and each layer includes multiple earth presses distributed in an array, and the earth press is connected to a static strain gauge outside the model box through a cable to monitor the soil pressure of the test soil in the model box; the stress sheet is installed on the outer walls around the jacking pipe, and the stress sheet is connected to the static strain gauge through a cable to monitor the stress on the outer walls around the jacking pipe.

[0015] On the other hand, an indoor test simulation method for rectangular pipe jacking curve construction is provided, characterized in that it includes the following steps: S1. Take the moisture content and soil particle size distribution as variables, prepare the corresponding test soil according to the designed test plan, and then fill the prepared test soil evenly in layers in the box; S2. Use a press to compact the soil. When the soil pressure corresponding to the required density is reached, stop compacting. Fill the soil again and compact the next layer in the same way. When the corresponding burial depth is reached, perform heap loading and pressurization treatment. S3, install the jacking platform mechanism and the jacking pipe mechanism, and seal the jacking pipe at the reserved pipe hole, adjust the horizontal height of the jacking pipe, and after the jacking pipe is adjusted, push the jacking pipe through the jacking mechanism. During the jacking process, the soil cutting device is used to excavate the test soil, and the Jiaolong excavation mechanism is synchronized to transport the excess soil inside the jacking pipe to the outside of the model box; S4. During the process of jacking the pipe into the test soil in the model box, the axial line of the pipe can be deviated by controlling the deviation correction mechanism, thereby completing the jacking of the curved section; S5. According to the excavation posture of the jacking pipe, the multi-tube grouting system is controlled to inject slurry into the four outer surfaces of the jacking pipe respectively, so as to realize the simulation test of the friction reduction grouting of the jacking pipe, and the simulation test process of the friction reduction grouting is carried out until all the jacking pipes are completed; S6. Repeat steps S3 to S5 to complete the jacking of all design test schemes and record the construction parameters and organize the data.

[0016] Further preferably, in the step S2, an earth pressure gauge is buried in the middle of the soil layer of the test soil, the earth pressure gauge is distributed in an array, the earth pressure gauge (cable is externally connected to the corresponding interface of the static strain gauge, the static strain gauge is connected to the computer, and debugging is completed; In the step S3, stress gauges are installed on the outer walls of the top pipe, and the stress gauge cables are externally connected to the corresponding interfaces of the static strain gauges. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an indoor test simulation system in an embodiment of the present invention; Figure 2 In the embodiment of the present invention Figure 1 A partial enlarged schematic diagram of Figure 3 It is a structural schematic diagram of a simulation system grouting system in an embodiment of the present invention; Figure 4 It is a right side view of the indoor test simulation system in the embodiment of the present invention; Figure 5 The simulation system in the embodiment of the present invention Figure 4 A partial enlarged schematic diagram of Figure 6 A top view of an indoor test simulation system in an embodiment of the present invention; Figure 7 It is a cross-sectional view of the deviation-correcting bolt in an embodiment of the present invention.

[0018] In the figure: 1. model box; 11. box body; 12. test soil; 13. reserved pipe hole; 2. jacking platform mechanism; 21. support frame; 211. fixed frame; 212. adjustable support foot; 22. jacking slide rail device; 221. groove track; 222. slide rail; 223. roller; 3. jacking mechanism; 31. jacking pipe; 311. machine head; 312. front pipe section; 313. rear pipe section; 314. grouting hole; 32. jacking mechanism; 321. jacking bracket; 322. jacking oil cylinder; 323. hydraulic station; 324. pressure sensor; 4. soil cutting device; 41. cutter head; 411. middle jacking cutter; 412. gear box; 414. peripheral Top cutter; 42. First transmission shaft; 43. Cutterhead drive device; 44. Coupling; 5. Jiaolong excavation mechanism; 51. Excavation pipeline; 52. Spiral rack; 53. Rack drive device; 6. Multi-tube grouting system; 61. Grouting station; 611. Slurry tank; 612. Air compressor; 613. Piston; 614. Pressure gauge; 615. Electronic balance; 62. Main slurry outlet pipe; 63. Connector; 64. Auxiliary slurry outlet pipe; 7. Correction mechanism; 71. Limit baffle; 72. Correction bolt; 721. Right pressure plate; 722. Spring; 723. Left pressure plate; 724. Vertical rod; 73. Locking nut; 10. Displacement sensor; 101. Data acquisition unit. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that, in the description of the present invention, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0021] In addition, it should be understood that for the convenience of description, the sizes of various components shown in the drawings are not drawn according to the actual proportional relationship.

[0022] It should be noted that like reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined or described in one drawing, it will not require further detailed discussion and description in the description of the subsequent drawings.

[0023] like Figures 1 to 7 As shown, the present invention provides a technical solution: an indoor test simulation system for rectangular pipe jacking curve construction, including a model box 1, a jacking platform mechanism 2, a pipe jacking mechanism 3, a soil cutting device 4, a dragon excavation mechanism 5 and a multi-tube grouting system 6.

[0024] like Figure 1 , Figure 4 and Figure 6As shown, the model box 1 includes a box body 11 with an opening at the top and a test soil 12 filled in the box body 11, and a reserved pipe hole 13 is formed on the side wall of the box body 11. In the present invention, the model box 1 is a hexahedral structure, and the frame of the box body 11 of the model box 1 is welded by angle steel and steel bars. The side wall of the box body 11 is made of a high-strength transparent acrylic plate. The box body 11 is transparent and has a perspective function. The internal situation can be observed from the outside of the box body 11. At the same time, scales are set at the four side edges inside the box body 11, which is convenient for the test personnel to observe the vertical displacement of the soil in the box body 11 with the naked eye. Specifically, in the embodiment of the present invention, the front, back, left and right sides of the model box 1 are made of 30mm thick transparent acrylic plates, and the bottom surface is made of reinforced steel plates. At the same time, the box body 11 is reinforced with angle steel and steel bars around to ensure the safety and stability of the box body 11, and can safely withstand soil and pressure loads. The length dimension * height dimension * width dimension of the box body 11 is 2500mm*2000mm*1500mm. The model box 1 is provided with a lifting device at the bottom of the four side edges of the frame to facilitate the adjustment of the height of the model box 1; the lifting device is provided with a fixing mechanism. When the model box 1 is placed, the fixing mechanism is braked to prevent the model box 1 from becoming unstable during operation.

[0025] like Figure 1 , Figure 2 and Figure 5 As shown, the pushing platform mechanism 2 is located on a side of the model box 1 where a reserved pipe hole 13 is provided. The pushing platform mechanism 2 includes a supporting frame 21 and a jacking pipe slide rail device 22. The supporting frame 21 is placed on the ground to play a supporting and bearing role, and the jacking pipe slide rail device 22 is installed on the supporting frame 21.

[0026] Specifically, Figure 5As shown, the support frame 21 includes a fixed frame 211 and an adjustable foot 212. The adjustable foot 212 is installed at the bottom of the fixed frame 211. The adjustable foot 212 can adjust the lifting height of the fixed frame 211. The top pipe slide rail device 22 includes a groove rail 221, a slide rail 222 and a roller 223. The groove rail 221 is fixed to the fixed frame 211 on one side different from the groove notch. The slide rail 222 is respectively fixed to the two sides and the bottom of the groove of the groove rail 221. Along the axial direction of the slide rail 222, the roller 223 is rotatably connected to the slide rail 222. The top pipe 31 is located in the groove of the groove rail 221, and the outer wall of the top pipe 31 is in contact with the roller 223. In the embodiment of the present invention, a portion of the slide rails 222 are fixedly connected to both sides of the groove of the groove track 221, and the slide rails 222 on both sides of the groove of the groove track 221 are arranged along the extension direction of the groove track 221, and the other portion of the slide rails 222 are fixedly connected to the bottom of the groove of the groove track 221, and two rows of slide rails 222 are fixedly connected to the bottom of the groove of the groove track 221, and the two rows of slide rails 222 are arranged along the extension direction of the groove track 221, and the two rows of slide rails 222 are symmetrically distributed relative to the center line of the groove track 221.

[0027] like Figure 1 , Figure 2 , Figure 4 , Figure 5 and Figure 6 As shown, the jacking mechanism 3 includes a jacking pipe 31, a jacking mechanism 32 and a correction mechanism 7 arranged on both sides of the jacking pipe 31. Specifically, the correction mechanisms 7 arranged on both sides of the jacking pipe 31 are respectively abutted on the left and right groove side plates of the groove track 221. The jacking pipe 31 is placed on the jacking pipe slide rail device 22, specifically placed in the groove of the groove track 221. When the jacking pipe 31 is jacked, the left, right and lower side walls of the jacking pipe 31 are respectively pressed on the roller 223. The cross-sectional size of the jacking pipe 31 is slightly smaller than the reserved pipe hole 13 to meet the curved jacking process of the jacking pipe 31. The front end passes through the reserved pipe hole 13 and is buried in the model box 1. The rear end of the jacking pipe 31 is connected to the jacking mechanism 32. The jacking mechanism 32 can push the jacking pipe 31 so that the jacking pipe 31 can move linearly along its own axial direction, and by adjusting the deviation correction mechanisms 7 on the left and right sides, the jacking pipe 31 can be offset to the left or right during the jacking process, so that the jacking pipe 31 can meet the requirements of curved jacking in the model box along the jacking pipe slide rail device, breaking the problem that the existing jacking model test device can only simulate the construction process of linear jacking along a fixed route and the simulation situation is relatively single.

[0028] Specifically, Figure 2 and Figure 5As shown, the upper side wall of the top pipe 31 is arranged in parallel with the lower side wall, the left side wall of the top pipe 31 is arranged in parallel with the right side wall, the upper side wall is smoothly connected to the left side wall and the right side wall by an arc, and the lower side wall is smoothly connected to the left side wall and the right side wall by an arc, and the arc angle is matched with the circumferential surface of the peripheral top cutting knife 414, so that the cutting surface is smoother and the effective cutting area is greatly improved. The circumferential surface of the middle top cutting knife 411 is tangent to the upper side wall and the lower side wall, so that the excavation surface is a rectangular excavation surface. The top pipe 31 includes a machine head 311, a front pipe segment 312 and a rear pipe segment 313. The machine head 311 is fixedly connected to the front pipe segment 312 by bolts. In order to simulate the gap behind the wall between the machine head 311 and the actual pipe segment during the excavation process, the design size of the front pipe segment 312 is larger than the rear pipe segment 313 by a "simulated gap". Specifically, the design size of the front pipe segment 312 is larger than the rear pipe segment 313 by about 1mm to 1.5mm. The front pipe segment 312 and the rear pipe segment 313 are connected at the connecting position by a sealing strip. The size deviation between the front and rear pipe segments will cause an uneven gap between the pipe segment and the machine head 311, thereby forming a gap behind the wall during the excavation process. Finally, the gap behind the wall between the machine head 311 and the actual pipe segment during the excavation process can be better simulated.

[0029] Specifically, the front pipe section 312 and the rear pipe section 313 are made of 40mm thick transparent acrylic plates and are transparent and have a perspective function. The test personnel can observe the internal conditions from the outside of the front pipe section 312 and the rear pipe section 313; the whole diffusion process of the friction-reducing mud can be obtained, and the forming process of the mud sleeve can be obtained by further analysis. In the embodiment of the present invention, the width dimension * height dimension * length dimension * thickness dimension of the front pipe section 312 is 411mm*226mm*800mm*40mm, and the width dimension * height dimension * length dimension * thickness dimension of the rear pipe section 313 is 410mm*225mm*800mm*40mm.

[0030] like Figure 1 and Figure 6As shown, the jacking mechanism 32 includes a jacking support 321, a jacking cylinder 322 and a hydraulic station 323. The jacking support 321 is fixedly connected to the rear end of the jacking pipe 31, the jacking cylinder 322 is connected to the jacking support 321, and the hydraulic station 323 is used to provide pressure oil for the jacking cylinder 322. A pressure sensor 324 is arranged between the jacking cylinder 322 and the jacking support 321. The pressure sensor 324 is used to measure the jacking pressure of the jacking cylinder 322. The pressure sensor 324 is connected to an external data acquisition unit 101. The data acquisition unit 101 can monitor the pressure value of the pressure sensor 324 in real time to control the pressure oil flow rate delivered by the hydraulic station 323 to the jacking cylinder 322. Specifically, an overflow valve is arranged on the hydraulic station 323. The oil output of the hydraulic station 323 is accurately controlled by adjusting the overflow valve, thereby accurately controlling the jacking rate of the jacking pipe 31. The jacking rate of the jacking pipe 31 can be controlled at a minimum of 1 mm / min. The present invention advances the jacking pipe 31 by using a power system consisting of a jacking cylinder 322 and a hydraulic station 323 with relatively high control accuracy, and accurately controls the flow rate of pressure oil delivered to the jacking cylinder 322 by adjusting the overflow valve to better and more accurately control the pressure, which is more suitable for the straight curve jacking construction process of the jacking pipe model test device of the present invention.

[0031] like Figure 1 and Figure 2 As shown, the soil cutting device 4 includes a cutter disc 41, a first transmission shaft 42, a cutter disc drive device 43 and a coupling 44. The cutter disc 41 is arranged at the front end of the top pipe 31. The cutter disc 41 is connected to the cutter disc drive device 43 through the first transmission shaft 42. The cutter disc drive device 43 can drive the cutter disc 41 to rotate and cut the soil. The speed at which the cutter disc drive device 43 drives the cutter disc 41 to rotate is adapted to the jacking speed of the top pipe 31. The coupling 44 is used to connect the first transmission shaft 42 and the cutter disc drive device 43 to absorb and buffer the impact and vibration brought by the cutter disc drive device 43, so that the cutter disc 41 can efficiently and stably cut the soil. In the embodiment of the present invention, the cutter disc drive device 43 is a driving servo motor. At the same time, the driving servo motor is connected to an external control unit. The control unit can control the driving servo motor to adjust the rotation speed of the cutter disc 41. The minimum rotation speed of the cutter disc can be controlled at 1 rad / min to adapt to the jacking speed of the top pipe 31.

[0032] Specifically, the cutter disc 41 includes an intermediate top cutter 411, a gear box 412, a first gear, a peripheral top cutter 414, a second gear and a rack. The intermediate top cutter 411 is rigidly coaxially mounted on the end of the first transmission shaft 42. The gear box 412 is composed of two guard plates, both of which are sleeved on the first transmission shaft 42. The two guard plates are fixed to the inner wall of the top pipe 31, and an accommodating space is formed between the two guard plates. The first gear is located in the accommodating space, and the first gear is rigidly coaxially connected to the first transmission shaft 42. The peripheral top cutter 414 is rotatably connected to the gear box 412 through the second transmission shaft. The axis of the second transmission shaft is parallel to the axis of the first transmission shaft 42. The second gear is located in the accommodating space, and the second gear is rigidly coaxially connected to the second transmission shaft. The second gear and the first gear are connected through rack transmission. The cutter head 41 in the present invention specifically includes a middle top cutter 411 and four peripheral top cutters 414 arranged at the end corner positions, so that the effective cutting area of ​​the cutter head 1 can reach between 80% and 90%, further reducing the pressure on the face of the tunnel. The excavation surface formed by the cutting and excavation of the soil cutting device 4 is rectangular, which is suitable for the curved construction process of the rectangular jacking pipe of the present invention, and provides theoretical guidance for studying the stability of the excavation surface of the large-section rectangular jacking pipe and setting the support pressure.

[0033] like Figure 6 As shown, the Jiaolong excavation mechanism 5 includes an excavation pipe 51, a spiral rack 52 and a rack drive device 53. The excavation pipe 51 is fixedly connected to both sides of the inner wall of the top pipe 31 along the axial direction of the top pipe 31. The spiral rack 52 is located in the pipe of the excavation pipe 51. The rack drive device 53 is fixedly connected to the fixed frame 211 through a support frame. The rack drive device 53 is connected to the spiral rack 52 and is used to drive the spiral rack 52 to rotate and transport the soil cut by the soil cutting device to the outside of the model box 1. In the embodiment of the present invention, the rack drive device 53 is a controllable rotary motor, and a control switch is provided on the rotary motor. The control switch can control the rotation speed of the rotary motor 3, thereby accurately controlling the excavation amount.

[0034] like Figure 1 and Figure 2As shown, along the axial direction of the top pipe 31, the side walls of the front pipe section 312 and the rear pipe section 313 are provided with a plurality of grouting holes 314. The multi-tube grouting system 6 sprays grout to the outer wall of the top pipe 31 through the grouting holes 314 to reduce drag, ensuring smooth top pipe. The multi-tube grouting system 6 includes a grouting station 61, a main grouting pipe 62, a connector 63 and an auxiliary grouting pipe 64. The grouting station 61 is equipped with slurry. One end of the main grouting pipe 62 is connected to the grouting station 61, and the other end of the main grouting pipe 62 is connected to the auxiliary grouting pipe 64 through the connector 63. The number of the auxiliary grouting pipe 64 matches the number of the grouting holes 314, and the auxiliary grouting pipe 64 is connected to the grouting holes 314. In the embodiment of the present invention, a main slurry outlet pipe 62 passes through the rear reserved hole of the jacking bracket 321 into the front pipe section 312 and the rear pipe section 313. The main slurry outlet pipe 62 extends along the jacking direction of the jacking pipe 31, and connectors 63 are arranged at equal intervals in its extending direction. One end of the auxiliary slurry outlet pipe 64 is connected to the connector 63, and the other end is connected to the slurry outlet holes 314 of the front pipe section 312 and the rear pipe section 313; at the same time, the left and right side walls of the front pipe section 312 are each provided with four slurry outlet holes 314 arranged at equal intervals, the upper and lower side walls of the front pipe section 312 are each provided with eight slurry outlet holes 314 arranged at equal intervals, the left and right side walls of the rear pipe section 313 are provided with four slurry outlet holes 314 arranged at equal intervals, and the upper and lower side walls of the rear pipe section 313 are provided with eight slurry outlet holes 314 arranged at equal intervals.

[0035] Specifically, Figure 3 As shown, the grouting station 61 includes a slurry tank 611, an air compressor 612, a piston 613, a pressure gauge 614 and an electronic balance 615. The slurry tank 611 is a closed structure, and slurry is installed in the slurry tank 611. The slurry tank 611 is connected to the main slurry outlet pipe 62. The air compressor 612 is connected to the slurry tank 611 through the piston 613 and the air pipe. When grouting, high-pressure gas is introduced into the closed slurry tank 611 to increase the pressure in the slurry tank 611, so that the slurry in the slurry tank 611 is transported out through the grouting pipeline. In order to facilitate the observation of the pressure in the slurry tank 611, the pressure gauge 614 is used to measure the pressure of the slurry tank 611. A pressure gauge 614 is arranged above the slurry tank 611. The pressure gauge 614 is used to monitor the pressure in the slurry tank 611. By observing the pressure changes of the pressure gauge 614, the air intake pressure can be adjusted in time, so as to realize constant pressure grouting and make the grouting pressure controllable. The slurry tank 611 is placed on the weighing part of the electronic balance 615. During the grouting process, the reduction of the slurry in the slurry tank 611 can be observed in real time through the electronic balance 615, which can also reflect the grouting speed from the side and can also timely evaluate the slurry residue in the slurry tank 611 and add slurry in time to avoid affecting the normal progress of the experiment.

[0036] like Figures 5 to 7As shown, the deflection correction mechanism 7 is used to make the top pipe 31 deflect to the left or right in the jacking direction to meet the requirement that the top pipe 31 can achieve curved jacking, thereby simulating the process of the top pipe 31 in the curved jacking construction. The deflection correction mechanism 7 includes a limit baffle 71, a deflection correction bolt 72 and a locking nut 73. The lower part of the limit baffle 71 is fixed to the support frame 21. The screw of the deflection correction bolt 72 passes through the limit baffle 71 and the locking nut 73 in sequence, and the end face of the deflection correction bolt 72 is against the groove side wall of the groove track 221. By loosening the deflection correction bolt 72 set on the left side of the groove track 221, the top pipe 31 is deflected to the left in the jacking direction, or by loosening the deflection correction bolt 72 set on the right side, the top pipe 31 is deflected to the right in the jacking direction, thereby meeting the curved jacking construction process of the top pipe 31. At the same time, the axis deviation of the top pipe 31 in the jacking process can also be adjusted to prevent the top pipe 31 from deviating during jacking. At the same time, an accommodating cavity is formed at the end of the correcting bolt 72, in which the right pressure plate 721, the spring 722 and the left pressure plate 723 are installed in sequence, one end of the vertical rod 724 is welded to the left pressure plate 723, and the other end of the vertical rod 724 is against the groove side wall of the groove track 221.

[0037] The indoor test simulation system also includes soil pressure gauges, stress sheets and displacement sensors 10. The soil pressure gauges are arranged in multiple layers in the test soil 12 of the model box 1. Each layer includes multiple soil pressure gauges distributed in an array. The soil pressure gauges are connected to the static strain gauges outside the model box 1 through cables to monitor the soil pressure of the test soil 12 in the model box 1. The stress sheets are installed on the outer walls around the top pipe 31. The stress sheets are connected to the static strain gauges through cables to monitor the stress on the outer walls around the top pipe 31. The displacement sensor 10 is installed above the box body 11. The vertical displacement of the test soil 12 in the box body 11 can be effectively monitored through multiple displacement sensors 10, so as to detect the influence of the straight curve construction of the rectangular top pipe on the surrounding soil. The arrangement of the soil pressure gauges, stress sheets and displacement sensors 10 can enable the present invention to better simulate the disturbance of the top pipe 31 on the surrounding soil during the curve construction process and the interaction between the top pipe 31 and the test soil 12. In an embodiment of the present invention, the earth pressure gauges are buried in the test soil 12, and the earth pressure gauges are arranged in three layers with intervals of 15 cm, 15 cm, and 10 cm respectively. The earth pressure gauges in each layer are evenly arranged in a 4×5 array, with 20 earth pressure gauges arranged in each layer; or, the earth pressure gauges are arranged in three layers, and according to design requirements, 4×4 array earth pressure gauges are set at intervals of 20 cm, 15 cm, and 10 cm in the soil layer of each test soil 12 above the jacking pipe 31, with 16 earth pressure gauges arranged in each layer.

[0038] Specifically, when the indoor test simulation system is used, its working steps are as follows: S1. Filling: taking the water content and the particle size distribution of the soil as variables, according to the designed test plan, and preparing the corresponding test soil 12, then filling the box 11 with the prepared test soil 12 in layers and evenly, and then compacting it; S2. An earth pressure gauge is buried in the middle of the soil layer of the test soil 12. An array earth pressure gauge is set according to the design requirements. The earth pressure gauge cable is externally connected to the corresponding interface of the static strain gauge. The static strain gauge is connected to the computer and debugged. A pressure plate is installed. A press is used to compact the soil. During the compaction process, the reading of the earth pressure gauge is observed. When the soil pressure corresponding to the required density is reached, the compaction is stopped. The next layer is compacted in the same way again. When the corresponding burial depth is reached, the pile load and pressurization treatment is performed. S3, installing the displacement sensor 10 at a predetermined position of the box 11; S4, install the jacking platform mechanism 2 and the jacking pipe mechanism 3, seal and connect the front and rear pipe sections of the jacking pipe 31, seal the jacking pipe 31 with the box body, install stress gauges on the four pipe walls outside the jacking pipe 31, connect the strain gauge cables to the corresponding interfaces of the static strain gauges, adjust the horizontal height of the jacking pipe 31 through the adjustable feet 212, and after the jacking pipe 31 is adjusted, start the jacking oil cylinder 322 to jack the jacking pipe 31. During the jacking process, the test soil 12 is excavated through the soil cutting device 4, and the synchronous Jiaolong excavation mechanism transports the excess soil inside the jacking pipe 31 out; S5. During the process of jacking the pipe section into the test soil in the model box, the pipeline axis can be deviated by controlling the deviation correction mechanism, thereby completing the jacking of the curved section; S6. According to the excavation posture of the pipeline, the multi-tube grouting system is controlled to open the valves of each auxiliary pipe to inject drag-reducing slurry to the four outer surfaces of the pipe section, thereby realizing a simulation test of friction-reducing grouting of the jacking pipe, until all the jacking pipes 31 are completed; S7, record and save the readings of the soil pressure gauge, strain gauge 9 and pressure gauge 614 during the jacking process; S8. Repeat steps S4 to S7 to complete the jacking of all design test schemes and record the construction parameters and organize the data.

[0039] The rectangular jacking pipe model test device provided by the present invention has a simple structure and is easy to use. It can better simulate the disturbance of the pipe segment correction on the surrounding soil during the curved construction process of the rectangular jacking pipe 31 and the interaction between the jacking pipe 31 and the slurry. By setting the correction mechanism 7 at both ends of the groove track 221, the jacking pipe 31 can be offset during the construction process to achieve the jacking curve. At the same time, it also solves the problem that the axis deviation of the rectangular jacking pipe 31 is uncontrollable due to the torque of the cutter head 1 during the straight jacking process under laboratory conditions. Through the displacement sensor 10 set above the model box 1, the displacement of the soil surface caused by the jacking pipe 31 during the jacking process is sensed, and the construction parameters (such as jacking rate, cutter head speed, grouting pressure, etc.) are adjusted in time to maintain the pressure balance of the face. The cutter head 41 including a middle top cutter 411 and four peripheral top cutters 414 can achieve a rectangular excavation face cutting rate of between 80% and 90%, and cooperate with the double dragon excavation system to transport the cut soil out of the pipe segment, thereby ensuring that the face maintains a balanced state during the excavation process. Through the multi-tube grouting system, valves can be used to control the four grouting surfaces of the rectangular jacking pipe in contact with the soil during the jacking process to be grouted simultaneously or separately to meet the grouting drag reduction of the jacking pipe under different excavation postures, and then the effect of different pipe-slurry-soil contact conditions on reducing the friction between the jacking pipe section and the soil during the jacking process and the impact on the jacking construction can be compared, and the grouting method suitable for actual construction under different excavation postures can be selected. The pipe section made of transparent acrylic board can intuitively observe the diffusion of the drag reduction slurry after injection and the formation process of the rectangular slurry sleeve, providing useful reference and guidance for on-site construction, with strong practicality and good promotion value.

[0040] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An indoor test simulation system for rectangular pipe jacking curve construction, characterized in that: include: A model box (1), the model box (1) comprising a box body (11) with an open top, a reserved pipe hole (13) being formed on a side wall of the box body (11); A pushing platform mechanism (2), the pushing platform mechanism (2) being located on a side of the model box (1) where the reserved pipe hole (13) is provided, the pushing platform mechanism (2) comprising a supporting frame (21) and a pipe-pushing slide rail device (22) mounted on the supporting frame (21); A pipe jacking mechanism (3), the pipe jacking mechanism (3) comprising a pipe jacking (31), a jacking mechanism (32) and a deviation correction mechanism (7); the pipe jacking (31) is a square pipe, and along the circumferential direction of the square pipe axis, each adjacent two side surfaces have a smooth transition; the pipe jacking (31) is placed on the pipe jacking slide rail device (22), and the front end passes through the reserved pipe hole (13) and is buried in the mold box (1); the rear end of the pipe jacking (31) is connected to the jacking mechanism (32), and the deviation correction mechanism (7) is arranged on the left and right sides of the pipe jacking (31); A soil cutting device (4), wherein the soil cutting device (4) is built into the jacking pipe (31); A Jiaolong excavation mechanism (5) for conveying the soil cut by the soil cutting device to the outside of the model box (1); Multi-tube grouting system for simulating real-time grouting (6).

2. According to claim 1, an indoor test simulation system for rectangular pipe jacking curve construction is characterized in that: The jacking mechanism (32) comprises a jacking support (321), a jacking oil cylinder (322) and a hydraulic station (323); the jacking support (321) is fixedly connected to the rear end of the jacking pipe (31); the jacking oil cylinder (322) is connected to the jacking support; and the hydraulic station (323) is used to provide pressure oil to the jacking oil cylinder (322).

3. The indoor test simulation system for rectangular pipe jacking curve construction according to claim 1 is characterized in that: The soil cutting device comprises a cutter disc (41), a first transmission shaft (42) and a cutter disc driving device (43); the cutter disc (41) is arranged at the front end of the jacking pipe (31); the cutter disc (41) is connected to the cutter disc driving device (43) via the first transmission shaft (42); and the cutter disc driving device (43) can drive the cutter disc (41) to rotate and cut the soil.

4. The indoor test simulation system for rectangular pipe jacking curve construction according to claim 3 is characterized in that: The cutter disc (41) comprises a middle top cutter (411), a gear box (412), a first gear, a peripheral top cutter (414), a second gear and a rack; The intermediate top cutter (411) is rigidly coaxially mounted on the end of the first transmission shaft (42); The gear box (412) is composed of two guard plates, both of which are sleeved on the first transmission shaft (42), and the two guard plates are fixed to the inner wall of the top pipe (31), and a containing space is formed between the two guard plates; The first gear is located in the accommodating space, and the first gear is rigidly coaxially connected to the first transmission shaft (42); The peripheral top cutter (414) is rotatably connected to the gear box (412) via a second transmission shaft, and the axis of the second transmission shaft is parallel to the axis of the first transmission shaft (42); The second gear is located in the accommodating space, the second gear is rigidly coaxially connected to the second transmission shaft, and the second gear is connected to the first gear through the rack transmission.

5. The indoor test simulation system for rectangular pipe jacking curve construction according to claim 1 is characterized in that: Along the axial direction of the top pipe (31), a plurality of grouting holes (314) are provided on the surrounding side walls of the top pipe (31); The multi-tube grouting system (6) comprises a grouting station (61), a main slurry outlet pipe (62), a connector (63) and an auxiliary slurry outlet pipe (64); the grouting station (61) is filled with slurry; one end of the main slurry outlet pipe (62) is connected to the grouting station (61); the other end of the main slurry outlet pipe (62) is connected to the auxiliary slurry outlet pipe (64) via the connector (63); the number of the auxiliary slurry outlet pipes (64) matches the number of the grouting holes (314), and the auxiliary slurry outlet pipes (64) are connected to the grouting holes (314).

6. The indoor test simulation system for rectangular pipe jacking curve construction according to claim 1 is characterized in that: The jacking rail device (22) comprises a groove rail (221), a slide rail (222) and a roller (223); A side of the groove track (221) that is different from the groove notch is fixedly connected to the support frame (21); The slide rails (222) are respectively fixed to both sides of the groove and the bottom of the groove of the groove track (221); The roller (223) is rotatably connected to the slide rail (222) along the axial direction of the slide rail (222), the top tube (31) is located in the groove of the groove track (221), and the outer wall of the top tube (31) is in contact with the roller (223).

7. An indoor test simulation system for rectangular pipe jacking curve construction according to claim 6, characterized in that: The deflection correcting mechanism (7) comprises a limit baffle (71), a deflection correcting bolt (72) and a locking nut (73); the lower portion of the limit baffle (71) is fixedly connected to the support frame (21); the screw of the deflection correcting bolt (72) passes through the limit baffle (71) and the locking nut (73) in sequence; and the end face of the deflection correcting bolt (72) abuts against the groove side wall of the groove track (221).

8. The indoor test simulation system for rectangular pipe jacking curve construction according to claim 1 is characterized in that: The indoor test simulation system also includes an earth pressure gauge and a stress sheet; The soil pressure gauges are arranged in multiple layers in the test soil (12) of the model box (1), each layer comprising a plurality of the soil pressure gauges distributed in an array, and the soil pressure gauges are connected to static strain gauges outside the model box (1) via cables to monitor the soil pressure of the test soil (12) in the model box (1); The stress sheet is installed on the outer walls around the top pipe (31), and the stress sheet is connected to a static strain gauge via a cable to monitor the stress on the outer walls around the top pipe (31).

9. An indoor test simulation method for rectangular pipe jacking curve construction, characterized in that: The steps include: S1. Using the water content and the particle size distribution of the soil as variables, prepare the corresponding test soil (12) according to the designed test plan, and then fill the box (11) with the prepared test soil (12) in layers and evenly; S2. Use a press to compact the soil. When the soil pressure corresponding to the required density is reached, stop compacting. Fill the soil again and compact the next layer in the same way. When the corresponding burial depth is reached, perform heap loading and pressurization treatment. S3, installing the jacking platform mechanism (2) and the jacking pipe mechanism (3), and sealing the jacking pipe (31) at the reserved pipe hole (13), adjusting the horizontal height of the jacking pipe (31), and after the jacking pipe (31) is adjusted, jacking the jacking pipe (31) through the jacking mechanism (32), excavating the test soil (12) through the soil cutting device (4) during the jacking process, and synchronously transporting the excess soil inside the jacking pipe (31) to the outside of the model box (1) through the Jiaolong excavation mechanism (5); S4, during the process of the jacking pipe (31) being pushed into the test soil (12) in the model box (1), the axial line of the jacking pipe (31) can be deflected by controlling the deviation correction mechanism (7), thereby completing the jacking of the curved section; S5, according to the excavation posture of the jacking pipe (31), controlling the multi-tube grouting system (6) to inject grouting material into the four outer surfaces of the jacking pipe (31) respectively, thereby realizing a simulation test of friction reduction grouting of the jacking pipe (31), and the simulation test process of friction reduction grouting is carried out until all the jacking pipes (31) are pushed forward; S6. Repeat steps S3 to S5 to complete the jacking of all design test schemes and record the construction parameters and organize the data.

10. An indoor test simulation method for rectangular pipe jacking curve construction according to claim 9, characterized in that: In the step S2, an earth pressure gauge is buried in the middle of the soil layer of the test soil (12), the earth pressure gauge is distributed in an array, the earth pressure gauge cable is externally connected to the corresponding interface of the static strain gauge, the static strain gauge is connected to the computer, and debugging is completed; In step S3, stress sheets are installed on the outer walls of the top pipe (31) on all four sides, and the stress sheet cables are externally connected to the corresponding interfaces of the static strain gauges.

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