A load box using a self-service in-cylinder grouting jack

Abstract

The present invention relates to a load box used in a self-balancing static load test of a foundation pile, in particular to a load box with multiple jacks inside. A load box using a self-service cylinder grouting jack comprises an upper plate, a lower plate and a hydraulic device, the hydraulic device comprises a liquid inlet pipe, a liquid outlet pipe, a cylinder body and a piston, the cylinder body is a cavity inside; the piston is fitted with the cavity gap, and its bottom surface is partially in contact with the bottom surface of the cavity, thereby forming a solution cavity; there are multiple hydraulic devices, and the adjacent liquid inlet pipes and liquid outlet pipes are connected in series through a connecting pipe, and the upper plate, the lower plate, the piston and the cylinder body move together. The present invention has the following advantages: 1. The slurry quality is guaranteed and the filling rate is improved. 2. It ensures that the engineering pile meets the design requirements of pull-out resistance. 3. It ensures the strength and integrity of the foundation pile body. 4. It ensures that the grouting body outside the cylinder is a high-purity pure slurry. 5. The upper plate structure is convenient for laying pipelines connecting each load box. 6. Multiple cylinders are connected in series, which can realize the overall liquid addition, drainage and grouting of the load box.

Description

Technical Field

[0001] The invention relates to a load box used in a self-balancing static load test of a pile foundation, in particular to a load box with a plurality of jacks inside. Background Art

[0002] In the self-balancing static load test of pile foundation, the load box used generally has only one liquid injection tube, so that after the test, the space between the cylinder and the piston of the load box is filled with a non-solidifying liquid. As a result, after the self-balancing static load test of the pile foundation, the liquid in the load box cylinder is squeezed out and the pile is displaced under the vertical compression state of the project.

[0003] Although some load boxes can achieve drainage and grouting through two pipes, since the two pipes are at the same elevation on the side of the upper end of the cylinder body, during grouting, only the liquid above the outlet elevation can be squeezed out, and the liquid below the outlet elevation cannot be completely drained, resulting in the injected slurry being diluted by the retained liquid, thereby reducing the concentration of the slurry, so that the final setting strength of the slurry is seriously reduced, and the reinforcement requirements cannot be met. Summary of the invention

[0004] The purpose of the present invention is to solve the problems existing in the prior art and to provide a load box using a self-service in-cylinder grouting jack, which can realize grouting while ensuring the quality of the slurry and improving the filling rate.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a load box using a self-service cylinder grouting jack, comprising an upper plate, a lower plate and a hydraulic device, the hydraulic device comprising a liquid inlet pipe, a liquid outlet pipe, a cylinder body and a piston, the cylinder body is a cavity, and the axial direction of the cavity is consistent with the axial direction of the cylinder body; the piston is matched with the cavity gap, and its bottom surface is partially in contact with the bottom surface of the cavity, thereby forming a solution cavity, through holes I and through holes II connected to the solution cavity are opened in the piston, the top of through hole I is connected to the liquid inlet pipe, and the top of through hole II is connected to the liquid outlet pipe, and a pipe groove, an elastic member and a hollow long tube are designed in through hole II, one end of the elastic member is fixed to the top of the pipe groove, and the other end is connected and fixed to the hollow long tube, the hollow long tube extends out of through hole II, and a plurality of openings opened at the bottom thereof are close to the bottom surface of the cavity and are connected to the solution cavity; there are multiple hydraulic devices, and the adjacent liquid inlet pipes and liquid outlet pipes are connected in series through connecting pipes, and the upper plate, the lower plate, the piston and the cylinder body move together.

[0006] Furthermore, it also includes an anti-pullout lock structure, which is used to limit the piston in the cylinder body when it moves upward. It includes an anti-pullout lock head and an anti-pullout lock groove that match each other. The anti-pullout lock head is arranged at the upper position of the cylinder body, and its head end faces the side wall of the piston; the anti-pullout lock groove is arranged at the lower position of the piston, and its open end faces the inner wall of the cylinder body.

[0007] Preferably, the anti-pullout lock includes a lock head, a spring and a base connected in sequence, the lock head is restricted in the through hole by the piston, the base is fixed to the cylinder body, and the spring is compressed between the lock head and the base.

[0008] Preferably, there are at least two anti-pullout lock structures, which are arranged opposite to each other.

[0009] Preferably, a sealing groove is provided on the side wall of the piston for accommodating a sealing ring, and the sealing groove is located below the anti-pullout locking groove.

[0010] Furthermore, it also includes a pressure-limited explosive grouting device, which includes a vertical pipe for grouting outside the cylinder and a reversing pipe. There are two vertical pipes for grouting outside the cylinder, which are used for grouting outside the cylinder and a protective sleeve for the lower displacement wire. The lower displacement wire is fixed in the vertical pipe for grouting outside the cylinder. Both ends of the reversing pipe are respectively inserted into the vertical pipe for grouting outside the cylinder, and the horizontal part of the reversing pipe is fixed to the lower plate.

[0011] Preferably, a pressure relief valve is installed in the reversing tube, the pressure relief valve includes a pressure relief channel, a solid pressure limiting plate and a hollow screw, the solid pressure limiting plate is arranged between the pressure relief channel and the hollow screw, and its pressure limiting value is less than the pressure bearing value of the reversing tube.

[0012] Preferably, a pressure relief valve is provided on the side wall of the cylinder body, the pressure relief valve comprises a pressure relief channel, a solid pressure limiting plate and a hollow screw, the opening of the pressure relief channel is provided on the inner wall of the cylinder body, and the solid pressure limiting plate is provided between the pressure relief channel and the hollow screw.

[0013] Preferably, the upper plate adopts a rigid lattice structure.

[0014] Preferably, an H-shaped waterproof connecting guard plate is installed between the upper plate and the lower plate, the rigid side plate of the upper plate is inserted into the upper part thereof and fixed, and the rigid side plate of the lower plate is inserted into the lower part thereof.

[0015] Preferably, the H-shaped waterproof connecting guard plate is made of flexible waterproof material.

[0016] Preferably, a sealing ring groove is provided around the circumference of the upper portion of the hollow long tube for accommodating the sealing ring.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The pipe groove, elastic parts and hollow long tube are designed in through hole II to ensure the cavity in the cylinder before grouting, so that the grouting body in the cylinder body is high-purity pure slurry, which ensures the slurry quality and improves the filling rate.

[0019] 2. The pull-out lock structure not only ensures that the piston is limited within the cylinder body when it is active, but also enables the load box to effectively transmit the pull-out force to the lower steel cage through the pull-out lock when the upper steel cage is subjected to upward pull-out force, ensuring that the engineering piles meet the pull-out design requirements after the self-balancing static load test of the foundation piles.

[0020] 3. The setting of the pressure-limited explosive grouting device fills the gap between the cylinder bodies, ensuring the strength and integrity of the foundation pile body, so that it can effectively transfer the load on the upper part of the load box to the pile body below the load box.

[0021] 4. The H-shaped waterproof connecting guard plate forms a closed circle around the entire side of the load box, so that after the pile self-balancing test, the piston in the cylinder of the load box will not be displaced due to loading, and the groundwater around the pile will penetrate and wrap the outside of the cylinder, ensuring that the grouting outside the cylinder is high-purity pure slurry.

[0022] 5. The upper plate of the load box adopts a rigid grid structure instead of a steel plate, which is convenient for laying pipes connecting the load boxes; after pouring concrete, the grid components are combined with concrete to form a high-strength rigid concrete slab.

[0023] 6. Multiple cylinders are connected in series through their top connecting pipes to realize the overall liquid filling, drainage and grouting of the load box. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0025] Figure 2 for Figure 1 Schematic diagram of the hydraulic device structure;

[0026] Figure 3 for Figure 1 Schematic diagram of the hollow long tube structure;

[0027] Figure 4 for Figure 1 Schematic diagram of the structure of the medium-resistant pullout lock;

[0028] Figure 5 for Figure 1 Schematic diagram of the structure of the medium pressure relief valve;

[0029] Figure 6 for Figure 1 Schematic diagram of the structure of the medium-limited-pressure explosive grouting device;

[0030] Figure 7 for Figure 1 Schematic diagram of the structure of the middle and upper plate;

[0031] Figure 8 for Figure 1 Schematic diagram of the structure of the middle and lower plates;

[0032] Fig. 9 for Figure 1 Schematic diagram of some structures;

[0033] Fig.10 for Figure 1 Schematic diagram of the starting and ending states of the hydraulic device;

[0034] Figure 1Among them, 1. Hydraulic device; 2. Upper plate; 3. Waterproof connecting guard plate; 4. Lower plate; 5. Connecting pipe; 6. Pressure-limited explosive grouting device;

[0035] Figure 2 7, liquid inlet pipe; 8, liquid outlet pipe; 9, upper fixing bolt; 10, lower fixing bolt; 11, cylinder body; 12, piston; 13, pipe groove; 14, spring; 15, sealing ring; 16, hollow long tube; 17, anti-pullout lock head; 18, pressure relief valve; 19, anti-pullout lock groove; 20, sealing groove and sealing ring;

[0036] Figure 3 In the middle, 21, sealing ring groove; 22, opening;

[0037] Figure 4 In the middle, 23, lock; 24, spring; 25, base;

[0038] Figure 5 Among them, 26, pressure relief channel; 27, solid pressure limiting plate; 28, hollow screw;

[0039] Figure 6 Among them, 34, lower displacement wire; 35, lower displacement wire sheath and external grouting vertical conduit; 36, reversing pipe; 18, pressure relief valve;

[0040] Figure 7 In the middle, 30, frame and lattice beam; 31, upper rigid side plate;

[0041] Figure 8 In the middle, 32, bottom plate; 33, lower rigid side plate. DETAILED DESCRIPTION

[0042] It should be noted that in the following embodiments of the present invention, the directional words are described according to the drawings and do not constitute a limitation to the present invention.

[0043] The following is combined with Figure 1-10 The present invention is further described in detail: a load box using a self-service cylinder grouting jack, such as Figure 1 As shown, it is composed of a hydraulic device 1, an upper plate 2, a waterproof connecting guard plate 3, a lower plate 4, a connecting pipe 5 and a pressure-limited explosive grouting device 6; the hydraulic device 1 is installed between the upper plate 2 and the lower plate 3, and there are multiple hydraulic devices, which are connected in series through the connecting pipe 5; the upper plate 2 is a rigid frame structure, the waterproof connecting guard plate 3 is made of flexible material, and is movably connected with the upper plate 2 and the lower plate 4, and the pressure-limited explosive grouting device 6 is installed on the lower plate 4.

[0044] like Figure 2-3As shown, the hydraulic device 1 includes an inlet pipe 7, an outlet pipe 8, a cylinder body 11 and a piston 12. The bottom of the cylinder body 11 is fixed to the lower plate 4 by a lower fixing bolt 10, and the interior thereof is a cavity, and the axial direction of the cavity is consistent with the axial direction of the cylinder body 11; the piston 12 is fixed to the upper plate 2 by an upper fixing bolt 9, and is inserted into the cavity and matches with the cavity gap, and its bottom surface is partially in contact with the bottom surface of the cavity, thereby forming a solution cavity, and a liquid inlet hole and a liquid outlet hole that are consistent with the axial direction of the cylinder body 11 are opened on the piston, and the liquid inlet hole and the liquid outlet hole are both connected to the solution cavity, the top of the liquid inlet hole is connected to the liquid inlet pipe 7, and the top of the liquid outlet hole is connected to the liquid outlet pipe 8; a pipe groove 13, a spring 14 and a hollow long tube 16 are designed in the liquid outlet hole, the axial direction of the pipe groove 13 is consistent with the axial direction of the liquid outlet hole, its radial dimension is slightly larger than the radial dimension of the liquid outlet hole, and its top is located in the liquid outlet hole, It is in the shape of a ladder, with the bottom flush with the bottom of the liquid outlet, the top of the spring 14 is connected and fixed to the top of the pipe groove, and the bottom is connected and fixed to the top of the hollow long tube 16, and the spring 14 is compressed in the pipe groove 13; the bottom of the hollow long tube 16 extends out of the liquid outlet and is close to the bottom of the solution cavity, and is connected to the solution cavity through a plurality of openings 22 opened at its bottom. When a pressurized air pump is used to supply air from the liquid inlet pipe 7 for pressurization, the air pressure will press the liquid in the cylinder body 11 from the opening of the hollow long tube 16 to the hollow long tube and be discharged through the hollow long tube, ensuring the cavity in the cylinder body 11 before grouting, so as to achieve a high-purity pure slurry in the cylinder body after grouting; due to the gap between the hollow long tube 16 and the pipe groove 13, in order to ensure complete liquid discharge, a sealing ring groove 21 is opened around the axis of the upper part of the hollow long tube 16, which is used to install the sealing ring 15 to ensure the sealing between the hollow long tube 16 and the liquid outlet.

[0045] In order to ensure that the piston 12 is limited in the cylinder body 11 when it is active, and at the same time, when the upper end steel cage is subjected to upward pulling force, the load box can effectively transmit the pulling force to the lower steel cage, thereby ensuring that the engineering pile meets the pull-out design requirements after the self-balancing static load test of the foundation pile, an anti-pulling lock device is added between the piston and the cylinder body, such as Figure 2 , Figure 4As shown, the anti-pulling lock device includes an anti-pulling lock head 17 and an anti-pulling lock groove 19 that match each other. The anti-pulling lock head 17 is arranged at the upper position of the cylinder body 11, and includes a lock head 23, a spring 24 and a base 25 that are connected in sequence. The head end of the lock head 23 is arc-shaped and faces the outer wall of the piston 12. The spring 24 is compressed between the lock head 23 and the base 25. The base is fixed to the cylinder body 11. The anti-pulling lock groove 19 is arranged at the lower position of the piston, and its open end faces the inner wall of the cylinder body 11. When the piston 12 moves upward to the position where the anti-pulling lock head 17 and the anti-pulling lock groove 19 are opposite, the lock head 23 is ejected into the anti-pulling lock groove 19 under the action of the spring 24, thereby locking the piston and the cylinder body so that they no longer move relative to each other. In order to achieve a better anti-pullout effect, two anti-pullout locking devices are designed and are relatively arranged in the two side walls of the cylinder body 11; of course, the anti-pullout locking structure is not limited to two, it can be multiple, and is generally designed according to the anti-pullout requirements (assuming that the anti-pullout capacity of each anti-pullout lock is a, and the overall anti-pullout requirement is b, then the number n≥b / a).

[0046] like Figure 2 As shown, since there is a gap between the piston 12 and the cylinder body 11, in order to prevent water or slurry from leaking from the gap during the loading process, sealing grooves and sealing rings 20 are provided on opposite sides of the piston 12 to ensure the sealing effect. The sealing groove is located below the anti-pullout lock groove 19.

[0047] In order to make the reinforced load box and the engineering pile form a continuous whole, ensure the strength and integrity of the foundation pile body, and effectively transfer the load on the upper part of the load box to the pile body below the load box, a pressure-limited explosive grouting device is added, such as Figure 5-6 As shown, the pressure-limited explosive grouting device 6 includes a lower displacement wire 34, a lower displacement wire sheath and external grouting vertical conduit 35, a reversing pipe 36 and a pressure relief valve 18. The lower displacement wire 34 is fixed in the lower displacement wire sheath and external grouting vertical conduit 35; the lower displacement wire sheath and external grouting vertical conduit 35 is two, which are respectively installed at the two ends of the reversing pipe 36, and the cylinder external grouting vertical pipe and the sheath pipe of the lower displacement wire are integrated into a multifunctional pipe, which can prevent the lower displacement wire 34 from being gripped by concrete and can also be used as a vertical conduit for grouting outside the cylinder; the two ends of the reversing pipe 36 are respectively inserted into the lower displacement wire sheath and external grouting vertical conduit 35. The displacement wire sheath and external grouting vertical conduit 35, the horizontal part of which is welded and fixed to the lower plate 4, thereby playing a role in diversion; at the same time, the free ends of the lower displacement wire sheath and external grouting vertical conduit 35 and the reversing tube 36 are both extended out of the upper plate 2, and the vertical part length L of the reversing tube 36 should be greater than the displacement value of the piston 12 when the self-balancing static load pile test is terminated; the pressure relief valve 18 is installed in the reversing tube 36, which includes a pressure relief channel 26, a solid pressure limiting plate 27 and a hollow screw 28, and the solid pressure limiting plate 27 is arranged between the pressure relief channel 26 and the hollow screw 28, and its pressure limit value P a Less than the pressure bearing capacity P of the reversing tube 36 b When the loading pressure value is P a, P b When the slurry breaks through the solid pressure limiting plate 27, the pressure is released by the hollow screw 28, and the slurry fills the gap between the lower plate 4 and the waterproof connecting guard plate 3. In order to fill the gaps between the hydraulic devices with slurry, Figure 2 As shown, a pressure relief valve 18 is added to the side wall of the cylinder body 11. The pressure relief valve 18 here has the same structure as the pressure relief valve in the pressure-limiting explosive grouting device. The opening of the pressure relief channel 26 is arranged on the inner wall of the cylinder body 11, and the solid pressure-limiting plate 27 is arranged between the pressure relief channel and the hollow screw 28.

[0048] like Figure 7-9 As shown, the upper plate 2 is a rigid lattice structure, which includes a frame and a lattice beam 30, and an upper rigid side plate 31. The frame and the lattice beam 30 are the upper surface of the upper plate, and the upper rigid side plate 31 is arranged around the frame and the lattice beam 30. Figure 8 As shown, the lower plate 4 includes a bottom plate 32 and a lower rigid side plate 33. The bottom plate 32 is a rigid plate with a hollow center, that is, the bottom plate 32 is annular, and the lower rigid side plate 33 is arranged around the bottom plate 32. The upper plate 2 and the lower plate 4 are connected together through a waterproof connecting guard plate 3. The waterproof connecting guard plate 3 is H-shaped, made of flexible waterproof material, and has a plurality of vent holes so that the upper rigid side plate 31 and the lower rigid side plate 33 can be inserted. The upper part of the H-shape encloses and fixes the upper rigid side plate 31 of the upper plate 2, and the lower part of the H-shape encloses the lower rigid side plate 33 of the lower plate 4. When the load box is filled with liquid and pressurized, the lower rigid side plate 33 of the lower plate 4 is gradually withdrawn along with the piston 12 of the hydraulic device 1.

[0049] like Fig.10 As shown, water is injected into the cavity through the liquid inlet pipe 7. As the amount of water increases, the cylinder body 11 moves downward relative to the piston 12, and the spring 14 presses the hollow long tube 16 so that its bottom is always in close contact with the bottom of the cylinder body. When the anti-pullout lock groove 19 moves to be opposite to the anti-pullout lock head 17, the anti-pullout lock head 17 pops out to lock the piston 12 and the cylinder body 11 so that they no longer move relative to each other.

[0050] Implementation steps:

[0051] (i) Liquid injection and pressurization: When liquid injection and pressurization is performed, the liquid outlet pipe 8 is closed and liquid is injected from the liquid inlet pipe 7;

[0052] 1. When there is no pressure, the piston is in the initial position, the spring is under pressure, and the pressure value is P1=P2=P3=P4. Fig.10 (a) as shown;

[0053] 2. Start pressurizing, close the liquid outlet pipe 8, and pressurize from the liquid adding pipe 7; the spring always supports the hollow long tube to make it close to the bottom of the cylinder body, and the pressure value is P1>P2>P3>P4;

[0054] 3. Continue to inject liquid and pressurize. When the anti-pullout lock groove 19 on the piston 12 reaches the position of the anti-pullout lock head 17, the anti-pullout lock head 17 pops out and locks the piston so that it can no longer move. When the termination condition is reached, the pressure value P1=P2=P3=P4, such as Fig.10 (b) as shown;

[0055] (ii) Inflation and drainage: After the liquid injection is completed, inflation and drainage begin. During inflation and drainage, the liquid inlet pipe 7 and the liquid outlet pipe 8 are not closed;

[0056] 4. Start to inflate and discharge liquid: Inject gas from the liquid inlet pipe 7, the gas fills into the cylinder 11 from top to bottom, squeezes the liquid and discharges it from the liquid outlet pipe 8, the pressure value is P1>P2>P3>P4;

[0057] 5. Continue to inflate until the liquid outlet pipe 8 stops discharging liquid, indicating that the liquid in the cylinder has been exhausted. Stop inflating. After stopping, the pressure value is P1=P2=P3=P4;

[0058] (iii) Grouting: When the liquid outlet pipe 8 stops discharging liquid, grouting begins;

[0059] 6. Start grouting: inject from the liquid inlet pipe 7, the pressure value is P1>P2>P3>P4;

[0060] 7. Continue grouting until slurry overflows from the outlet pipe and then stops. After stopping, the pressure value is P1=P2=P3=P4;

[0061] (IV) Grouting into the pressure-limited explosive grouting device

[0062] 8. After closing the lower displacement wire sheath and external grouting vertical conduit at one end, continue grouting until grout overflows from the other side of the pipe and take samples;

[0063] 9. After sampling, close the overflow end, and then inject the slurry at high pressure from the inlet end until the pressure relief valve explodes, forcing the slurry to flow naturally and fill the gaps between the two sides.

[0064] In this embodiment, water is used as the loading liquid, which has better affinity with the slurry and lower cost than oil.

[0065] The above embodiment is only a preferred embodiment of the present invention and does not constitute a limitation of the present invention. The anti-pullout locking device can exist in any load box structure using the jack principle. The pressure-limited explosive grouting device and the anti-pullout locking device can exist in the same embodiment at the same time, or they can exist separately in different embodiments. That is, the pressure-limited explosive grouting device is suitable for any load box structure. In other words, in the above embodiment, the anti-pullout locking device, the pressure-limited explosive grouting device and the hydraulic device can be matched in various ways to achieve different purposes and different technical effects. Any extension, deformation, etc. made by ordinary technicians in this field without departing from the working principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A load box using a self-service cylinder grouting jack, comprising an upper plate, a lower plate and a hydraulic device, characterized in that: The hydraulic device comprises a liquid inlet pipe, a liquid outlet pipe, a cylinder body and a piston. The interior of the cylinder body is a cavity, and the axial direction of the cavity is consistent with the axial direction of the cylinder body. The piston is fitted with the cavity gap, and its bottom surface is partially in contact with the bottom surface of the cavity, thereby forming a solution cavity. A through hole I and a through hole II connected to the solution cavity are provided in the piston. The top of through hole I is connected to the liquid inlet pipe, and the top of through hole II is connected to the liquid outlet pipe. A pipe groove, an elastic member and a hollow long tube are designed in through hole II. One end of the elastic member is fixed to the top of the pipe groove, and the other end is connected and fixed to the hollow long tube. The hollow long tube extends out of through hole II, and a plurality of openings provided at the bottom thereof are close to the bottom surface of the cavity and are connected to the solution cavity. There are multiple hydraulic devices, and the adjacent liquid inlet pipes and liquid outlet pipes are connected in series through connecting pipes. The upper plate moves with the piston, and the lower plate moves with the cylinder body.

2. The load box using the self-service in-cylinder grouting jack according to claim 1, characterized in that: It also includes an anti-pullout lock structure, which is used to limit the piston in the cylinder body when it moves upward. It includes an anti-pullout lock head and an anti-pullout lock groove that match each other. The anti-pullout lock head is arranged at the upper position of the cylinder body, and its head end faces the side wall of the piston; the anti-pullout lock groove is arranged at the lower position of the piston, and its open end faces the inner wall of the cylinder body.

3. The load box using the self-service in-cylinder grouting jack according to claim 2, characterized in that: The anti-pullout lock comprises a lock, a spring and a base which are connected in sequence. The lock is restricted in a through hole by a piston, the base is fixed to a cylinder body, and the spring is compressed between the lock and the base.

4. The load box using the self-service cylinder grouting jack according to claim 2 or 3, characterized in that: There are at least two anti-pullout lock structures, which are arranged opposite to each other.

5. The load box using the self-service in-cylinder grouting jack according to claim 1, characterized in that: A sealing groove is provided on the side wall of the piston for accommodating a sealing ring, and the sealing groove is located below the anti-pullout lock groove.

6. The load box using the self-service in-cylinder grouting jack according to claim 1, characterized in that: It also includes a pressure-limited explosive grouting device, which includes an external grouting vertical pipe and a reversing pipe. There are two external grouting vertical pipes, which are used for external grouting and a lower displacement wire protective sleeve. The lower displacement wire is fixed in the external grouting vertical pipe. Both ends of the reversing pipe are respectively inserted into the external grouting vertical pipe, and the horizontal part of the reversing pipe is fixed to the lower plate.

7. The load box using the self-service in-cylinder grouting jack according to claim 6, characterized in that: A pressure relief valve is installed in the reversing tube. The pressure relief valve includes a pressure relief channel, a solid pressure limiting plate and a hollow screw. The solid pressure limiting plate is arranged between the pressure relief channel and the hollow screw, and its pressure limiting value is less than the pressure bearing value of the reversing tube.

8. The load box using the self-service in-cylinder grouting jack according to claim 1, characterized in that: A pressure relief valve is arranged on the side wall of the cylinder body, and the pressure relief valve comprises a pressure relief channel, a solid pressure limiting plate and a hollow screw. The opening of the pressure relief channel is arranged on the inner wall of the cylinder body, and the solid pressure limiting plate is arranged between the pressure relief channel and the hollow screw.

9. The load box using the self-service in-cylinder grouting jack according to claim 1, characterized in that: The upper plate adopts a rigid grid structure.

10. The load box using the self-service in-cylinder grouting jack according to claim 1, characterized in that: An H-shaped waterproof connecting guard plate is installed between the upper plate and the lower plate, the rigid side plate of the upper plate is inserted into the upper part and fixed, and the rigid side plate of the lower plate is inserted into the lower part.

11. The load box using the self-service in-cylinder grouting jack according to claim 10, characterized in that: The H-shaped waterproof connection guard plate is made of flexible waterproof material.

12. The load box using the self-service in-cylinder grouting jack according to claim 1, characterized in that: A sealing ring groove is provided on the upper part of the hollow long tube around its circumference for accommodating the sealing ring.

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