A reinforcement structure for a tower crane foundation platform on the side of a deep foundation pit and a displacement control method

Abstract

A deep foundation pit side tower crane bearing platform reinforcement structure and displacement control method. Anchor tension piles are provided on both sides outside the tower crane bearing platform. An anchor tension pile capping beam is provided at the top of the anchor tension piles. The anchor tension pile capping beam is connected to the foundation pit retaining structure through a tie beam. The anchor tension pile capping beam and the tower crane bearing platform are separated, solving the problem of excessive horizontal displacement and settlement of the hoisting bearing platform caused by the conflict between the anchor tension pile capping beam and the tower crane bearing platform. In addition, a number of grouting pipes are pre-pressed and set between the foundation pit retaining structure and the tower crane bearing platform. During the construction process of the deep foundation pit, when the inclination of the tower crane approaches the preset required value, expansive cement slurry is pressurized and injected into the soil between the foundation pit retaining structure and the tower crane bearing platform through the grouting pipes. By using the volume expansion generated during the hydration and hardening process of the expansive cement slurry, the horizontal and vertical displacements of the tower crane bearing platform are actively compensated and controlled, achieving the purpose of actively controlling the horizontal displacement and settlement of the tower crane bearing platform.

Description

Technical Field

[0001] The present invention relates to the technical field of safety control technology for tower cranes adjacent to deep foundation pit construction, and particularly relates to a reinforcement structure for a tower crane foundation on the side of a deep foundation pit and a displacement control method. Background Art

[0002] At present, the development and utilization of urban underground space has become an important means to alleviate urban problems such as land shortage and traffic congestion. Therefore, there are more and more construction projects such as underground garages, underground transportation, and underground civil and industrial facilities. When the above-mentioned engineering projects are constructed by the open cut method and the excavation area is large, tower cranes need to be set around the deep foundation pit to assist in the transportation and installation of construction materials. However, the excavation of the deep foundation pit will cause the horizontal displacement and settlement of the surrounding soil. To prevent the horizontal displacement and settlement of the soil around the deep foundation pit from having a safety impact on the tower crane set around it, the "Safety Code for Tower Cranes" emphasizes that the tower crane foundation should be set in an area where the bearing capacity of the foundation meets the requirements and is stable, and avoid areas that may be affected by foundation pit excavation, dewatering, and soil sliding. In addition, to prevent the adverse impact of external additional loads outside the foundation pit on the foundation pit support structure, in the "Technical Code for Building Foundation Pit Support", it is required to maintain a certain safety distance from the construction loads (including tower cranes) around the deep foundation pit. Generally speaking, this distance is at least 1.5 to 2 times the depth of the foundation pit.

[0003] With the rapid development of the city, the construction land for construction projects is becoming increasingly tense, and the construction range line of deep foundation pits for underground garages, underground transportation, and underground civil and industrial facilities is getting closer and closer to the land red line. Therefore, it is necessary to set the tower crane near the edge of the deep foundation pit enclosure structure, resulting in the inability to meet the safety distance required for construction loads (including tower cranes) around the deep foundation pit in the "Technical Code for Building Foundation Pit Support". The soil under the tower crane foundation set at the edge of the deep foundation pit will inevitably have horizontal displacement and settlement during the construction process of the deep foundation pit, which seriously threatens the safety of the tower crane operation. Therefore, how to solve the above problems has become a technical problem faced in the construction of deep foundation pits for underground garages, underground transportation, and underground civil and industrial facilities in the city.

[0004] In view of the above problems, in the article "Reinforcement Design and Deformation Control Analysis of Tower Crane Foundation Next to Deep Foundation Pit", a reinforcement technical scheme for the tower crane foundation next to the deep foundation pit is proposed, in which a cap support pile is arranged under the tower crane cap, anchor rods are arranged on the deep foundation pit maintenance structure, and anchor piles are arranged on the outside of the tower crane cap. The anchor piles are connected to the deep foundation pit maintenance structure through additional tension beams. This reinforcement scheme achieves the effect of simultaneously reinforcing the deep foundation pit maintenance structure and the tower crane cap, thereby reducing the horizontal displacement and vertical settlement of the tower crane cap and the deep foundation pit maintenance structure during the deep foundation pit construction process. However, there are two problems in this technical solution: 1. The connecting beam between the anchor piles on the outside of the tower crane pedestal conflicts with the tower crane pedestal. During the construction of the deep foundation pit, the horizontal displacement of the deep foundation pit maintenance structure will actually be transmitted to the tower crane pedestal through the connecting beam between the anchor piles, resulting in the horizontal displacement and settlement of the tower crane pedestal still being relatively large (reaching 7.37mm and 5.46mm respectively); 2. In this solution, the horizontal displacement and settlement of the tower crane pedestal can only be passively monitored during the construction of the deep foundation pit, but the horizontal displacement and settlement of the tower crane pedestal cannot be actively controlled. Once the horizontal displacement and settlement of the tower crane pedestal are too large, it will still endanger the working safety of the tower crane. Therefore, the technical solution for strengthening the tower crane foundation on the side of the deep foundation pit needs to be further improved. Summary of the invention

[0005] In order to overcome the deficiencies in the background technology, the present invention discloses a tower crane pedestal reinforcement structure and a displacement control method for a deep foundation pit side, so as to solve the problems in the existing technical solutions for reinforcing the tower crane foundation on the side of a deep foundation pit, namely, large horizontal displacement and settlement of the tower crane pedestal and lack of active control measures for the horizontal displacement and settlement of the tower crane pedestal.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a tower crane pedestal reinforcement structure at the side of a deep foundation pit, comprising a foundation pit retaining structure and a tower crane pedestal arranged adjacent to the outside of the foundation pit retaining structure, a pedestal support pile is arranged at the lower part of the tower crane pedestal; anchor piles are arranged on both sides of the outer side of the tower crane pedestal, an anchor pile crown beam is arranged on the top of the anchor pile, the anchor pile crown beam is connected to the foundation pit retaining structure by a tension beam, and the anchor pile crown beam is separately arranged from the tower crane pedestal; during the construction of the deep foundation pit, the anchor piles apply tension to the foundation pit retaining structure through the tension beam, thereby reducing the deformation of the foundation pit retaining structure, thereby reducing the horizontal displacement and vertical settlement of the tower crane pedestal, and preventing the verticality of the tower crane from exceeding the tolerance problem.

[0007] Furthermore, monitoring points are fixedly arranged at the four corners of the upper part of the tower crane pedestal.

[0008] Furthermore, a number of grouting pipes are pre-pressed and installed between the foundation pit retaining structure and the tower crane bearing platform. During the construction of the deep foundation pit, expansive cement slurry is pressure-injected into the soil between the foundation pit retaining structure and the tower crane bearing platform through the grouting pipes. By utilizing the volume expansion generated during the hydration and hardening process of the expansive cement slurry, the horizontal and vertical displacements of the tower crane bearing platform are actively compensated and controlled, achieving the purpose of actively controlling the horizontal displacement and settlement of the tower crane bearing platform.

[0009] Furthermore, the anchor pile capping beam at the top of the anchor tie pile is connected through the anchor tie pile connecting beam, and there is a separated setting between the anchor tie pile connecting beam and the tower crane bearing platform. A number of reinforcement anchor cables are arranged outside the anchor tie pile connecting beam. A reinforcement anchor cable seat is fixedly arranged on the exposed part of the reinforcement anchor cable on the ground, and a fixed pulley is rotatably arranged on the reinforcement anchor cable seat. A bearing platform reinforcement steel wire rope is arranged on the fixed pulley. Wire rope anchor seats are fixedly arranged on the anchor tie pile connecting beam and the tower crane bearing platform corresponding to the fixed pulley. The bearing platform reinforcement steel wire rope bypasses the fixed pulley, and both ends are respectively connected to the wire rope anchor seats on the anchor tie pile connecting beam and the tower crane bearing platform. A pre-tension force is applied to the bearing platform reinforcement steel wire rope through a core-piercing hydraulic lifter.

[0010] Furthermore, during the construction of the deep foundation pit, two rows of retaining structure reinforcement anchor cables are successively arranged on the foundation pit retaining structure, reducing the deformation of the foundation pit retaining structure, thereby reducing the displacement of the tower crane bearing platform in the horizontal direction and the settlement in the vertical direction, and preventing the problem of excessive deviation of the tower crane verticality.

[0011] Furthermore, the grouting pipe includes an outer grouting pipe, an inner grouting pipe, and a spring. A number of grouting holes are arranged in an array on the outer walls of the outer grouting pipe and the inner grouting pipe. The bottom of the outer grouting pipe is provided with a closed conical head, and the bottom of the inner grouting pipe is provided with a closed flat bottom. The inner grouting pipe is movably arranged in the outer grouting pipe, and the spring is arranged between the bottom of the outer grouting pipe and the inner grouting pipe. Under normal conditions, the grouting holes of the outer grouting pipe and the inner grouting pipe are mutually misaligned. During grouting, the inner grouting pipe compresses the spring, making the grouting holes of the outer grouting pipe and the inner grouting pipe communicate with each other.

[0012] Furthermore, a limit pin is fixedly arranged near the lower part of the outer grouting pipe, and a limit groove is arranged on the flat bottom at the bottom of the inner grouting pipe. The limit pin is stuck in the limit groove to prevent the inner grouting pipe from rotating in the outer grouting pipe.

[0013] A displacement control method for the reinforcement structure of the tower crane bearing platform on the side of the deep foundation pit. During the construction of the deep foundation pit, the horizontal displacement and vertical displacement of the four monitoring points on the upper part of the tower crane bearing platform are detected at a set period, and the inclination of the tower crane is calculated. When the tower crane is inclined and the inclination is close to the preset required value, expansive cement slurry is pressure-injected into the soil between the foundation pit retaining structure and the tower crane bearing platform through the grouting pipe. By utilizing the volume expansion generated during the hydration and hardening process of the expansive cement slurry, the horizontal and vertical displacements generated by the tower crane bearing platform are actively compensated, preventing the problem of excessive deviation of the tower crane verticality.

[0014] Furthermore, when the tower crane inclines and the inclination degree approaches the preset required value, the prestress of the bearing platform reinforcement steel wire rope is increased through the core-pulling hydraulic jack to actively compensate for the horizontal and vertical displacements generated by the tower crane bearing platform, preventing the problem of excessive deviation of the tower crane verticality.

[0015] Due to the adoption of the above technical solution, the present invention has the following beneficial effects: A deep foundation pit side tower crane bearing platform reinforcement structure and displacement control method disclosed by the present invention are provided with anchor-pulling piles on both sides outside the tower crane bearing platform. The top of the anchor-pulling piles is provided with an anchor-pulling pile capping beam. The anchor-pulling pile capping beam is connected to the foundation pit retaining structure through a tie beam. The anchor-pulling pile capping beam and the tower crane bearing platform are separated, thus solving the problem that the horizontal displacement and settlement of the tower crane bearing platform are still relatively large caused by the conflict between the anchor-pulling pile capping beam and the tower crane bearing platform. In addition, a number of grouting pipes are pre-pressed and arranged in the soil between the foundation pit retaining structure and the tower crane bearing platform. During the construction process of the deep foundation pit, when the inclination degree of the tower crane approaches the preset required value, expansive cement slurry is pressurized and injected into the soil between the foundation pit retaining structure and the tower crane bearing platform through the grouting pipes. By utilizing the volume expansion generated during the hydration and hardening process of the expansive cement slurry, the horizontal and vertical displacements generated by the tower crane bearing platform are actively compensated and controlled, achieving the purpose of actively controlling the horizontal displacement and settlement of the tower crane bearing platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic plan view of the deep foundation pit side tower crane bearing platform reinforcement structure in Embodiment 1;

[0017] Figure 2 It is a schematic sectional view of the deep foundation pit side tower crane bearing platform reinforcement structure in Embodiment 1;

[0018] Figure 3 It is for attachment Figure 2 Partial enlarged view of A;

[0019] Figure 4 It is a schematic plan view of the deep foundation pit side tower crane bearing platform reinforcement structure in Embodiment 3;

[0020] Figure 5 It is a schematic sectional view of the deep foundation pit side tower crane bearing platform reinforcement structure in Embodiment 3;

[0021] Figure 6 It is a schematic plan view of the deep foundation pit side tower crane bearing platform reinforcement structure in Embodiment 5;

[0022] Figure 7 It is a schematic sectional view of the deep foundation pit side tower crane bearing platform reinforcement structure in Embodiment 5;

[0023] Figure 8 It is a schematic external view of the grouting pipe;

[0024] Figure 9 It is a schematic sectional structure view of the grouting pipe;

[0025] Figure 10 For attachment Figure 9 A magnified schematic diagram of the cross-sectional structure of the grouting pipe in a normal state;

[0026] Figure 11 For attachment Figure 9 An enlarged schematic diagram of the cross-sectional structure of the grouting pipe when it is working.

[0027] In the figure: 1. Foundation pit retaining piles; 2. Retaining pile crown beam; 3. Tower crane cap; 4. Cap support piles; 5. Reinforcement anchor cables for retaining structure; 6. Anchor piles; 7. Anchor pile crown beam; 8. Tension beam; 9. Grouting pipe; 9.1. External grouting pipe; 9.1.1. External grouting hole; 9.2. Internal grouting pipe; 9.2.1. Internal grouting hole; 9.2.2. Limiting groove; 9.3. Limiting pin; 9.4. Spring; 10. Anchor pile connecting beam; 11. Reinforcement anchor cable; 12. Reinforcement anchor cable seat; 13. Cap reinforcement wire rope; 14. Ground-connected wall; 15. Tower crane; 16. Core-penetrating hydraulic lifter; 17. Monitoring point. DETAILED DESCRIPTION

[0028] The present invention can be explained in detail by the following examples, and the purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention.

[0029] Example 1, see the attached specification Figure 1 , 2 , 3:

[0030] A tower crane cap reinforcement structure on the side of a deep foundation pit. Taking a project in Wuhan as an example, the excavation area of the bottom edge of the foundation pit is about 34585.38 square meters, the perimeter of the foundation pit is about 745.43 m, the leveling elevation of the site around the foundation pit is 22.50 m, the elevation of the bottom plate of the foundation pit is 11.50 m, and the average excavation depth of the foundation pit is 11.00 m, which belongs to a first-level foundation pit; the foundation pit retaining structure adopts a ground-connected wall 14 structure with a depth of 18m and a thickness of 800mm; the tower crane cap structure on the side of the deep foundation pit includes: a ground-connected wall 14, a tower crane cap 3, anchor piles 6, a reinforcement anchor cable 11, and a pre-buried grouting pipe 9;

[0031] The outer edge of the tower crane cap 3 is 1.2 meters from the outer edge of the ground connecting wall, the maximum lifting height of the tower crane is 51 meters, the plane size of the tower crane cap 3 is 5 meters * 5 meters, the burial depth is 1.5 meters, and the lower part of the tower crane cap 3 is provided with four cap support piles 4, with a diameter of 800 mm, a spacing of 3.6 meters, and a length of 20 meters; monitoring points 17 are fixedly set at the four corners of the upper part of the tower crane cap 3. During the deep foundation pit construction process, the horizontal and vertical displacement changes of the monitoring points 17 are measured regularly by an omnidirectional instrument to monitor the horizontal and vertical displacement changes of the tower crane cap 3;

[0032] Two groups of anchor tie piles 6 are respectively arranged on both outer sides of the tower crane foundation platform 3. Each group of anchor tie piles 6 contains two anchor tie piles 6. The spacing within each group of anchor tie piles 6 is 1.2 m, and the spacing between groups of anchor tie piles 6 is 8 m. The diameter of the anchor tie piles 6 is 800 mm, and the length is 15 m. At the top of each group of anchor tie piles 6, an anchor tie pile capping beam 7 is connected. The anchor tie pile capping beams 7 are connected by an anchor tie pile connecting beam 10 (actually, the anchor tie pile capping beam 7 and the anchor tie pile connecting beam 10 are an integral structure, and they only have different installation positions). The anchor tie pile capping beam 7 and the diaphragm wall 14 are connected by a tie beam 8. The widths of the anchor tie pile capping beam 7, the anchor tie pile connecting beam 10, and the tie beam 8 are 1.2 m, and the thicknesses are 1.0 m. The anchor tie pile connecting beam 10 is separately arranged from the tower crane foundation platform 3, and the spacing between them is 500 mm. During the construction process of the deep foundation pit, as the excavation depth of the deep foundation pit increases, the soil pressure on the inner side of the diaphragm wall 14 disappears. Under the action of the soil pressure on the outer side of the deep foundation pit, the diaphragm wall 14 will have a horizontal displacement and settlement towards the inner side of the deep foundation pit. At this time, the anchor tie piles 6 apply a tensile force to the diaphragm wall 14 through the tie beam 8, playing a role in strengthening and reinforcing the diaphragm wall 14 and reducing the deformation of the diaphragm wall 14. The reduction of the deformation amount of the diaphragm wall 14 will correspondingly also reduce the horizontal displacement and vertical settlement amount of the soil between the tower crane foundation platform 3 and the diaphragm wall 14, thereby reducing the displacement of the tower crane foundation platform 3 in the horizontal direction and the settlement in the vertical direction. In this embodiment, while the anchor tie piles 6 reduce the deformation of the diaphragm wall 14 through the tie beam 8, actually, the anchor tie pile capping beam 7 and the anchor tie pile connecting beam 10 at the upper part of the anchor tie piles 6 also have a horizontal displacement and settlement towards the diaphragm wall 14 direction. However, due to the separate arrangement of the anchor tie pile connecting beam 10 and the tower crane foundation platform 3, compared with the existing reinforcement technical solutions for tower crane foundations on the side of deep foundation pits, the influence of the horizontal displacement and settlement (especially the horizontal displacement) of the anchor tie pile capping beam 7 and the anchor tie pile connecting beam 10 on the tower crane foundation platform 3 is extremely small, thus greatly improving the horizontal displacement and settlement of the tower crane foundation platform 3.

[0033] Seven grouting pipes 9 with a diameter of 100 mm are pre-pressed and arranged between the diaphragm wall 14 and the tower crane foundation platform 3. The grouting pipes 9 are pressed into the soil between the diaphragm wall 14 and the tower crane foundation platform 3 through a hydraulic penetration system; see the attached Figures 8 - 11: The length of the grouting pipe 9 is 11 m (equal to the excavation depth of the foundation pit), including an outer grouting pipe 9.1, an inner grouting pipe 9.2, and a spring 9.4; a number of outer grouting holes 9.1.1 are arranged in an array on the outer wall of the outer grouting pipe 9.1, and a number of inner grouting holes 9.2.1 are arranged in an array on the outer wall of the inner grouting pipe 9.2. The diameters of the outer grouting holes 9.1.1 and the inner grouting holes 9.2.1 are both 10 mm; a closed cone head is provided at the bottom of the outer grouting pipe 9.1 by welding (the cone head is used to reduce the resistance when the grouting pipe 9 is pressed into the soil), and a limit pin 9.3 is fixedly arranged on the outer grouting pipe 9.1 near the upper part of the cone head; the bottom of the inner grouting pipe 9.2 is provided with a closed flat bottom, and a limit groove 9.2.2 is arranged on the flat bottom. The inner grouting pipe 9.2 is movably arranged in the outer grouting pipe 9.1, and the limit pin 9.3 is stuck in the limit groove 9.2.2 to prevent the inner grouting pipe 9.2 from rotating in the outer grouting pipe 9.1; the spring 9.4 is arranged between the bottom of the outer grouting pipe 9.1 and the inner grouting pipe 9.2; see the attached drawing of the specification Figure 10 , under normal conditions, the inner grouting pipe 9.2 maintains its original position under the support of the spring 9.4. At this time, the outer grouting holes 9.1.1 of the outer grouting pipe 9.1 and the inner grouting holes 9.2.1 of the inner grouting pipe 9.2 are staggered in the up and down positions. Therefore, the outer grouting holes 9.1.1 and the inner grouting holes 9.2.1 are not connected, preventing soil from entering the inner grouting pipe 9.2 when the grouting pipe 9 is pressed into the soil between the diaphragm wall 14 and the tower crane platform 3, resulting in the blockage of the lower grouting holes of the grouting pipe 9 during grouting; see the attached drawing of the specification Figure 11, during the construction of the deep foundation pit, when it is monitored that the horizontal and vertical displacements of the tower crane platform 3 towards the deep foundation pit approach or exceed the preset values, the expansive cement slurry can be pressurized and injected into the soil between the diaphragm wall 14 and the tower crane platform 3 through the pre-pressed grouting pipe 9. When the expansive cement slurry enters the inner grouting pipe 9.2, it will exert a downward pressure on the inner grouting pipe 9.2. This pressure overcomes the elastic force of the spring 9.4, causing the inner grouting pipe 9.2 to move downward along the guiding of the limiting groove 9.2.2. At this time, the outer grouting hole 9.1.1 is connected to the inner grouting hole 9.2.1, and the expansive cement slurry in the inner grouting pipe 9.2 is injected into the soil between the diaphragm wall 14 and the tower crane platform 3 through the connected outer grouting hole 9.1.1 and inner grouting hole 9.2.1; after the expansive cement slurry is injected into the soil, it expands in volume during the hydration and hardening processes, increasing the soil pressure between the diaphragm wall 14 and the tower crane platform 3, compensating for the horizontal and vertical displacements of the tower crane platform 3, and achieving the purpose of actively controlling the horizontal displacement and settlement of the tower crane platform; in the deep foundation pit side tower crane platform reinforcement structure of the present invention, using the pre-pressed grouting pipe 9 instead of drilling to grout the soil between the diaphragm wall 14 and the tower crane platform 3 is to prevent the problem of the aggravation of the horizontal and vertical displacements of the tower crane platform 3 caused by soil loss during the drilling process; in addition, when grouting the soil through the seven pre-pressed grouting pipes 9, the seven grouting pipes 9 are divided into two groups (the two groups of grouting pipes 9 are arranged at intervals) and implemented twice. Therefore, there are actually two opportunities to actively control the horizontal displacement and settlement of the tower crane platform through the pre-pressed grouting pipes 9;

[0034] Four reinforcement anchor cables 11 are also arranged at 2.5 m outside the anchor pile connecting beam 10. The aperture of the anchor cable is φ130 mm, the inclination angle is 70°, bottom-hole pressure reverse grouting is adopted, a grout stopper is added at the hole mouth, and the grouting pressure is 0.5 - 0.8 MPa. The whole hole grouting is completed at one time; the reinforcement anchor cable 11 adopts 5 bundles of 1860-grade Φ15.24 high-strength low-relaxation prestressed steel strands, the designed tensile load of the anchor cable is 330 kN, and the anchoring length is 18 m; a reinforcement anchor cable seat 12 is fixedly arranged on the part of the reinforcement anchor cable 11 exposed on the ground; see the attached Figure 3, a fixed pulley is rotatably arranged above the reinforcement cable anchor seat 12, and a bearing platform reinforcement steel wire rope 13 is arranged on the fixed pulley; corresponding to the fixed pulley, a wire rope anchoring seat is fixedly arranged on the anchor pile connecting beam 10 and the tower crane bearing platform 3. The bearing platform reinforcement steel wire rope 13 bypasses the fixed pulley, and both ends are fixedly connected to the wire rope anchoring seats on the anchor pile connecting beam 10 and the tower crane bearing platform 3 respectively; a prestress of 120 kN is applied to the bearing platform reinforcement steel wire rope 13 through the core-passing hydraulic lifter 16 (this prestress is 60% of the maximum working tension of the bearing platform reinforcement steel wire rope 13, and a 40% working tension adjustment space of the bearing platform reinforcement steel wire rope 13 is reserved for actively controlling the horizontal displacement and settlement of the tower crane bearing platform). The core-passing hydraulic lifter 16 is controlled by a servo hydraulic system, and under normal circumstances, the working pressure of the core-passing hydraulic lifter 16 remains unchanged; during the construction process of the deep foundation pit, as the excavation depth of the deep foundation pit increases, the soil pressure inside the diaphragm wall 14 disappears. Under the action of the soil pressure outside the deep foundation pit, the diaphragm wall 14 will undergo horizontal displacement and vertical displacement towards the inside of the deep foundation pit. When the diaphragm wall 14 undergoes horizontal displacement and vertical displacement towards the inside of the deep foundation pit, it will apply a pulling force to the anchor pile capping beam 7 and the anchor pile connecting beam 10 through the tie beam 8, causing the anchor pile capping beam 7 and the anchor pile connecting beam 10 to generate horizontal and vertical displacements towards the deep foundation pit direction. The horizontal and vertical displacements of the anchor pile capping beam 7 and the anchor pile connecting beam 10 will be applied to the reinforcement cable anchor seat 12 through the bearing platform reinforcement steel wire rope 13 and the fixed pulley, thereby reducing the deformation of the diaphragm wall 14; in addition, when the anchor pile capping beam 7 and the anchor pile connecting beam 10 generate horizontal and vertical displacements towards the deep foundation pit direction, they will act on the tower crane bearing platform 3 in the reverse direction through the bearing platform reinforcement steel wire rope 13 that bypasses the fixed pulley, causing the tower crane bearing platform 3 to generate horizontal and vertical displacements away from the deep foundation pit direction, so as to actively compensate for part of the horizontal and vertical displacements of the tower crane bearing platform 3 towards the deep foundation pit direction caused by the deformation of the diaphragm wall 14 (the reason for the horizontal and vertical displacements of the tower crane bearing platform 3 towards the deep foundation pit direction caused by the deformation of the diaphragm wall 14 is that when the diaphragm wall 14 deforms, it will cause the pressure in the soil between the diaphragm wall 14 and the tower crane bearing platform 3 to decrease, and this decrease in soil pressure will cause the tower crane bearing platform 3 to undergo horizontal and vertical displacements towards the foundation pit direction). Therefore, the influence of the deformation of the diaphragm wall 14 on the tower crane bearing platform 3 is reduced, thereby further improving the horizontal displacement and settlement of the tower crane bearing platform 3; under normal circumstances, since the working pressure of the core-passing hydraulic lifter 16 remains unchanged, the core-passing hydraulic lifter 16 will automatically adjust the length of the reinforcement cable 11 between the anchor pile connecting beam 10 and the tower crane bearing platform 3, so that the prestress on the bearing platform reinforcement steel wire rope 13 always remains unchanged;During the construction of a deep foundation pit, when it is monitored that the horizontal and vertical displacements of the tower crane foundation platform 3 towards the deep foundation pit approach or exceed the preset values, the working pressure of the through-core hydraulic lifter 16 can be controlled by the servo hydraulic system to shorten the length of the reinforcing anchor cable 11 between the anchor pile connecting beam 10 and the tower crane foundation platform 3. After the length of the reinforcing anchor cable 11 is shortened, a greater pre-tension force will be applied to the anchor pile connecting beam 10 and the tower crane foundation platform 3 through the fixed pulley on the reinforcing anchor cable seat 12, so as to cause the anchor pile connecting beam 10 and the tower crane foundation platform 3 to generate horizontal and vertical displacements away from the deep foundation pit direction, thus realizing the active control of the horizontal displacement and settlement of the tower crane foundation platform; when the length of the reinforcing anchor cable 11 is shortened, there are differences in the horizontal and vertical displacements of the anchor pile connecting beam 10 and the tower crane foundation platform 3 away from the deep foundation pit direction, and this difference is automatically adjusted through the rotation of the fixed pulley on the reinforcing anchor cable seat 12.; Embodiment 2:

[0035] A displacement control method for the reinforcement structure of the tower crane foundation platform on the side of a deep foundation pit based on Embodiment 1. During the construction of the deep foundation pit, the horizontal displacement and vertical displacement of the four monitoring points 17 on the upper part of the tower crane foundation platform 3 are detected at a daily cycle, and the inclination of the tower crane is calculated; when the tower crane is inclined and the inclination approaches the preset required value, preferably, the working pressure of the four through-core hydraulic lifters 16 is synchronously controlled to increase through the servo hydraulic system, so as to shorten the length of the reinforcing anchor cable 11 between the anchor pile connecting beam 10 and the tower crane foundation platform 3. After the length of the reinforcing anchor cable 11 is shortened, a greater pre-tension force is applied to the anchor pile connecting beam 10 and the tower crane foundation platform 3 through the fixed pulley on the reinforcing anchor cable seat 12, so as to cause the anchor pile connecting beam 10 and the tower crane foundation platform 3 to generate horizontal and vertical displacements away from the deep foundation pit direction (in fact, it will also drive the diaphragm wall to generate horizontal and vertical displacements away from the deep foundation pit direction, but this displacement will be smaller than the displacement of the tower crane foundation platform 3, so the pressure in the soil between the tower crane foundation platform 3 and the diaphragm wall will decrease); when controlling the increase of the working pressure of the four through-core hydraulic lifters 16, the horizontal and vertical displacement changes of the four monitoring points 17 are measured in real time through the omnidirectional instrument until the horizontal and vertical displacements of the tower crane foundation platform 3 are stably controlled within the required range;

[0036] If the prestress applied to the reinforcement cable 11 reaches 80% (160 kN), but the horizontal and vertical displacements of the tower crane platform 3 still cannot reach the required range, four of the seven grouting pipes 9 pre-pressed into the soil between the diaphragm wall 14 and the tower crane platform 3 are activated (the four grouting pipes 9 are arranged at intervals). For the first time, expansive cement slurry is injected into the soil between the foundation pit retaining structure and the tower crane platform 3 at a set pressure and grouting volume; after the grouting is completed, the grouting pipes 9 are blocked, and the volume expansion generated during the hydration and hardening process of the expansive cement slurry is used to increase the pressure in the soil between the tower crane platform 3 and the diaphragm wall, compensating for the horizontal and vertical displacements of the tower crane platform 3; after the first grouting is completed, within 48 hours, the horizontal and vertical displacement changes of the monitoring point 17 are measured every two hours. If the horizontal and vertical displacement compensation of the tower crane platform 3 is too large and causes horizontal and vertical displacements in the opposite direction, it is necessary to reduce the prestress applied to the reinforcement cable 11 until the horizontal and vertical displacements of the tower crane platform 3 are stably controlled within the required range;

[0037] As the excavation depth of the deep foundation pit increases and the tower crane continues to work, if the tower crane tilts again, the working pressure of the four core-piercing hydraulic lifters 16 is synchronously controlled to increase through the servo hydraulic system until the horizontal and vertical displacements of the tower crane platform 3 are stably controlled within the required range;

[0038] If the prestress applied to the reinforcement cable 11 reaches 100% (200 kN), but the horizontal and vertical displacements of the tower crane platform 3 still cannot reach the required range, the remaining three of the seven grouting pipes 9 pre-pressed into the soil between the diaphragm wall 14 and the tower crane platform 3 are activated for the second time. For the second time, expansive cement slurry is injected into the soil between the foundation pit retaining structure and the tower crane platform 3 at a set pressure and grouting volume; after the grouting is completed, the grouting pipes 9 are blocked, and the volume expansion generated during the hydration and hardening process of the expansive cement slurry is used to compensate for the horizontal and vertical displacements generated by the tower crane platform 3; after the first grouting is completed, within 48 hours, the horizontal and vertical displacement changes of the monitoring point 17 are measured every two hours, and if necessary, the prestress applied to the reinforcement cable 11 is reduced until the horizontal and vertical displacements of the tower crane platform 3 are stably controlled within the required range.

[0039] Example 3, see the attached instructions Figure 4 、 5 :

[0040] A deep foundation pit side tower crane bearing platform reinforcement structure is applied to the working conditions where the soil bearing capacity at the project site is good and the groundwater is relatively deep (exceeding the depth of the deep foundation pit and no dewatering is required during excavation); in the deep foundation pit side tower crane bearing platform reinforcement structure of this embodiment, the foundation pit retaining structure adopts the foundation pit retaining pile 1 structure. The diameter of the foundation pit retaining pile 1 is 800 mm, the spacing is 1.2 m, the pile length is 18 m, and a retaining pile capping beam 2 is fixedly connected to the pile top; the outer edge of the tower crane bearing platform 3 is 2.5 m from the outer edge of the diaphragm wall. The maximum lifting height of the tower crane is 51 m. The plane size of the tower crane bearing platform 3 is 5 m * 5 m, and the buried depth is 1.5 m. Four bearing platform support piles 4 are provided under the tower crane bearing platform 3, with a diameter of 800 mm and a spacing of 3.6 m. The length of the bearing platform support pile 4 is 20 m;

[0041] On both sides of the outside of the tower crane bearing platform 3, two groups of anchor piles 6 are provided respectively. The inner spacing within each group of anchor piles 6 is 1.2 m, and the spacing between groups of anchor piles 6 is 8 m; the diameter of the anchor pile 6 is 800 mm and the length is 15 m; a capping beam 7 for the anchor pile is connected to the top of each group of anchor piles 6, and the two capping beams 7 for the anchor piles are separated (no anchor pile connecting beam 10 is provided in the middle); the capping beam 7 for the anchor pile is connected to the retaining pile capping beam 2 through a tie beam 8; the widths of the capping beam 7 for the anchor pile and the tie beam 8 are 1.2 m and the thickness is 1.0 m; the capping beam 7 for the anchor pile is separated from the tower crane bearing platform 3, and the spacing between the two is 500 mm; during the construction process of the deep foundation pit, as the excavation depth of the deep foundation pit increases, the soil pressure inside the foundation pit retaining pile 1 disappears. Under the action of the soil pressure outside the deep foundation pit, the foundation pit retaining pile 1 will have a horizontal displacement and settlement towards the inside of the deep foundation pit. At this time, the anchor pile 6 applies a tensile force to the retaining pile capping beam 2 at the upper part of the foundation pit retaining pile 1 through the tie beam 8, reducing the deformation of the foundation pit retaining pile 1; the reduction of the deformation amount of the foundation pit retaining pile 1 will correspondingly also reduce the horizontal displacement and vertical settlement of the soil between the tower crane bearing platform 3 and the foundation pit retaining pile 1, and further reduce the displacement in the horizontal direction and the settlement in the vertical direction of the tower crane bearing platform 3; in this embodiment, while the anchor pile 6 reduces the deformation of the foundation pit retaining pile 1 through the tie beam 8, in fact, the capping beam 7 for the anchor pile at the upper part of the anchor pile 6 also has a horizontal displacement and settlement towards the deep foundation pit direction. However, because the capping beam 7 for the anchor pile is separated from the tower crane bearing platform 3, compared with the existing reinforcement technical scheme for the tower crane foundation on the side of the deep foundation pit, the horizontal displacement and settlement (especially the horizontal displacement) of the capping beam 7 for the anchor pile have extremely little influence on the tower crane bearing platform 3, thus greatly improving the horizontal displacement and settlement of the tower crane bearing platform 3;

[0042] Seven grouting pipes 9 with a diameter of 100 mm are pre-pressed and set between the foundation pit retaining pile 1 and the tower crane platform 3. The grouting pipes 9 are pressed into the soil between the foundation pit retaining pile 1 and the tower crane platform 3 through a hydraulic penetration system. Expansive cement slurry is injected into the soil through the seven pre-pressed grouting pipes 9. The volume expansion generated during the hydration and hardening process of the expansive cement slurry is utilized to increase the soil pressure between the retaining pile 1 and the tower crane platform 3, compensate for the horizontal and vertical displacements generated by the tower crane platform 3, and achieve the purpose of actively controlling the horizontal displacement and settlement of the tower crane platform;

[0043] When the deep foundation pit is excavated to 2 m below the elevation of the top of the capping beam, the first waling beam and the retaining structure reinforcement cable 5 are set on the foundation pit retaining pile 1. The aperture of the cable is φ130 mm. Bottom-hole pressure reverse grouting is adopted, a grout stopper is added at the hole mouth, and the grouting pressure is 0.5 - 0.8 MPa. The whole hole grouting is completed at one time; the retaining structure reinforcement cable 5 adopts 5 bundles of 1860-grade Φ15.24 high-strength low-relaxation prestressed steel strands. The designed tension load of the cable is 330 kN, the anchorage length is 15 m, and the inclination angle is 15°; when the deep foundation pit is excavated to 4 m below the elevation of the top of the capping beam, the second waling beam and the retaining structure reinforcement cable 5 are set on the foundation pit retaining pile 1. The second waling beam and the retaining structure reinforcement cable 5 are exactly the same as the first one; in this embodiment, by setting two rows of retaining structure reinforcement cables 5 on the foundation pit retaining pile 1, the deformation of the foundation pit retaining pile 1 in the horizontal and vertical directions after the excavation of the deep foundation pit is improved, and further the purpose of reducing the horizontal displacement and settlement of the tower crane platform 3 is achieved;

[0044] In this embodiment, the structure of the grouting pipe 9 is different from that of Embodiment 1. The external grouting holes 9.1.1 of the external grouting pipe 9.1 and the internal grouting holes 9.2.1 of the internal grouting pipe 9.2 are only arranged on the side facing the tower crane platform 3 to prevent the premature leakage of the expansive cement slurry on the side of the foundation pit retaining pile 1 during the pressure grouting process. Embodiment Four:

[0045] A displacement control method for the reinforcement structure of the tower crane cap on the side of a deep foundation pit based on Embodiment 3. During the construction of the deep foundation pit, the horizontal and vertical displacements of the four monitoring points 17 on the upper part of the tower crane cap 3 are detected once a day, and the inclination of the tower crane is calculated. When the tower crane is inclined and the inclination is close to the preset required value, four of the seven grouting pipes 9 pre-pressed into the soil between the diaphragm wall 14 and the tower crane cap 3 are activated (the four grouting pipes 9 are arranged at intervals). For the first time, expansive cement slurry is injected into the soil between the foundation pit retaining structure and the tower crane cap 3 at a set pressure and grouting volume. After the grouting is completed, the grouting pipes 9 are blocked, and the volume expansion generated during the hydration and hardening process of the expansive cement slurry is used to compensate for the horizontal and vertical displacements generated by the tower crane cap 3. After the first grouting is completed, within 48 hours, the horizontal and vertical displacement changes of the monitoring points 17 are measured every two hours until the horizontal and vertical displacements of the tower crane cap 3 are stably controlled within the required range.

[0046] As the excavation depth of the deep foundation pit increases and the tower crane continues to work, if the tower crane is inclined again, the remaining three of the seven grouting pipes 9 pre-pressed into the soil between the diaphragm wall 14 and the tower crane cap 3 are activated for the second time. For the second time, expansive cement slurry is injected into the soil between the foundation pit retaining structure and the tower crane cap 3 at a set pressure and grouting volume. After the grouting is completed, the grouting pipes 9 are blocked, and the volume expansion generated during the hydration and hardening process of the expansive cement slurry is used to compensate for the horizontal and vertical displacements generated by the tower crane cap 3. After the first grouting is completed, within 48 hours, the horizontal and vertical displacement changes of the monitoring points 17 are measured every two hours until the horizontal and vertical displacements of the tower crane cap 3 are stably controlled within the required range.

[0047] Embodiment 5, see the attached Figure 6 、 7 :

[0048] A reinforcement structure for the tower crane cap on the side of a deep foundation pit. Based on the structure of Embodiment 3, it is connected between the anchor pile capping beams 7 through the anchor pile connecting beam 10. The anchor pile connecting beam 10 is separated from the tower crane cap 3, and the distance between the two is 500 mm. In addition, four reinforcement anchor cables 11 are arranged 2.5 m outside the anchor pile connecting beam 10. The aperture of the anchor cable is φ130 mm, the inclination angle is 70°, bottom-hole pressure reverse grouting is adopted, a grout stopper is added at the hole mouth, and the grouting pressure is 0.5 - 0.8 MPa. The whole-hole grouting is completed at one time. The reinforcement anchor cable 11 adopts 5 bundles of 1860-grade Φ15.24 high-strength low-relaxation prestressed steel strands, the designed tensile load of the anchor cable is 330 kN, and the anchorage length is taken as 18 m. The part of the reinforcement anchor cable 11 exposed on the ground is fixedly provided with a reinforcement anchor cable seat 12. See the attached Figure 3, a fixed pulley is rotatably arranged on the reinforcement cable anchor seat 12, and a bearing platform reinforcement steel wire rope 13 is arranged on the fixed pulley; wire rope anchor seats are fixedly arranged on the anchor-pulling pile connecting beam 10 and the tower crane bearing platform 3 corresponding to the fixed pulley. The bearing platform reinforcement steel wire rope 13 bypasses the fixed pulley, and both ends are fixedly connected to the wire rope anchor seats on the anchor-pulling pile connecting beam 10 and the tower crane bearing platform 3 respectively; a pre-tension of 120 kN is applied to the bearing platform reinforcement steel wire rope 13 through the core-piercing hydraulic lifter 16 (this pre-tension is 60% of the maximum working tension of the bearing platform reinforcement steel wire rope 13, leaving a 40% working tension adjustment space for actively controlling the horizontal displacement and settlement of the tower crane bearing platform). The core-piercing hydraulic lifter 16 is controlled by a servo-hydraulic system, and under normal circumstances, the working pressure of the core-piercing hydraulic lifter 16 remains unchanged; during the construction of the deep foundation pit, as the excavation depth of the deep foundation pit increases, the soil pressure inside the foundation pit retaining pile 1 disappears. Under the action of the soil pressure outside the deep foundation pit, the foundation pit retaining pile 1 will have horizontal and vertical displacements towards the inside of the deep foundation pit. When the foundation pit retaining pile 1 has horizontal and vertical displacements towards the inside of the deep foundation pit, it will apply a pulling force to the anchor-pulling pile capping beam 7 and the anchor-pulling pile connecting beam 10 through the tie beam 8, causing the anchor-pulling pile capping beam 7 and the anchor-pulling pile connecting beam 10 to have horizontal and vertical displacements towards the deep foundation pit direction. The horizontal and vertical displacements of the anchor-pulling pile capping beam 7 and the anchor-pulling pile connecting beam 10 will be applied to the reinforcement cable anchor seat 12 through the bearing platform reinforcement steel wire rope 13 and the fixed pulley, thereby reducing the deformation of the foundation pit retaining pile 1; in addition, when the anchor-pulling pile capping beam 7 and the anchor-pulling pile connecting beam 10 have horizontal and vertical displacements towards the deep foundation pit direction, they will act on the tower crane bearing platform 3 through the bearing platform reinforcement steel wire rope 13 bypassing the fixed pulley, causing the tower crane bearing platform 3 to have horizontal and vertical displacements away from the deep foundation pit direction, thereby compensating for part of the horizontal and vertical displacements of the tower crane bearing platform 3 towards the deep foundation pit direction caused by the deformation of the foundation pit retaining pile 1 (the reason for the horizontal and vertical displacements of the tower crane bearing platform 3 towards the deep foundation pit direction caused by the deformation of the foundation pit retaining pile 1 is that when the foundation pit retaining pile 1 deforms, it will cause the soil pressure in the soil between the foundation pit retaining pile 1 and the tower crane bearing platform 3 to decrease, and this decrease in soil pressure will cause the tower crane bearing platform 3 to have horizontal and vertical displacements towards the foundation pit direction). Therefore, the influence of the deformation of the foundation pit retaining pile 1 on the tower crane bearing platform 3 is reduced, further improving the horizontal displacement and settlement of the tower crane bearing platform 3; under normal circumstances, since the working pressure of the core-piercing hydraulic lifter 16 remains unchanged, the core-piercing hydraulic lifter 16 will automatically adjust the length of the reinforcement cable 11 between the anchor-pulling pile connecting beam 10 and the tower crane bearing platform 3, so that the pre-tension on the bearing platform reinforcement steel wire rope 13 always remains unchanged;When the deep foundation pit is under construction, it is monitored that when the horizontal and vertical displacements of the tower crane pedestal 3 in the direction of the deep foundation pit are close to or exceed the preset values, the working pressure of the core-penetrating hydraulic lifter 16 can be increased by controlling the servo hydraulic system, so that the length of the reinforcement anchor cable 11 between the anchor pile connecting beam 10 and the tower crane pedestal 3 becomes shorter. After the length of the reinforcement anchor cable 11 becomes shorter, a greater pre-tensioning force will be applied to the anchor pile connecting beam 10 and the tower crane pedestal 3 through the fixed pulley on the reinforcement anchor cable seat 12, so that the anchor pile connecting beam 10 and the tower crane pedestal 3 produce horizontal and vertical displacements away from the deep foundation pit, thereby realizing active control of the horizontal displacement and settlement of the tower crane pedestal; when the length of the reinforcement anchor cable 11 becomes shorter, there is a difference in the horizontal and vertical displacements of the anchor pile connecting beam 10 and the tower crane pedestal 3 away from the deep foundation pit, and the difference is automatically adjusted by rotating the fixed pulley on the reinforcement anchor cable seat 12;

[0049] In this embodiment, the method for controlling the displacement of the tower crane cap at the side of the deep foundation pit is the same as that in the second embodiment.

[0050] The parts not described in detail in this invention are prior art.

[0051] Those skilled in the art should understand that they can implement variations by combining the prior art and the above embodiments. Such variations do not affect the essence of the present solution and are not described in detail here.

[0052] It should be understood that the present solution is not limited to the above-mentioned specific implementation methods, and the structures and construction methods that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present solution without departing from the scope of the technical solution of the present solution, or modify it into an equivalent embodiment with equivalent changes, which does not affect the substantive content of the present solution. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present solution without departing from the content of the technical solution of the present solution still falls within the scope of protection of the technical solution of the present solution.

Claims

1. A reinforcement structure for a tower crane foundation platform on the side of a deep foundation pit, comprising a foundation pit retaining structure and a tower crane foundation platform (3) disposed adjacent to the outside of the foundation pit retaining structure, and a foundation platform support pile (4) is provided below the tower crane foundation platform (3); characterized in that: On both outer sides of the tower crane bearing platform (3), there are anchor tie piles (6). At the top of the anchor tie piles (6), there is an anchor tie pile capping beam (7). The anchor tie pile capping beam (7) is connected to the foundation pit retaining structure through a tie beam (8), and the anchor tie pile capping beam (7) and the tower crane bearing platform (3) are separated; the anchor tie pile capping beam (7) at the top of the anchor tie piles (6) is connected through an anchor tie pile connecting beam (10), and the anchor tie pile connecting beam (10) and the tower crane bearing platform (3) are separated; during the construction of the deep foundation pit, the anchor tie piles (6) apply tensile force to the foundation pit retaining structure through the tie beam (8), reducing the deformation of the foundation pit retaining structure, and further reducing the horizontal displacement and vertical settlement of the tower crane bearing platform (3), preventing the problem of excessive deviation of the tower crane verticality.

2. The deep foundation pit side tower crane bearing platform reinforcement structure according to claim 1, wherein: Monitoring points (17) are fixedly arranged at the four corners of the upper part of the tower crane bearing platform (3).

3. The deep foundation pit side tower crane bearing platform reinforcement structure according to claim 2, characterized in that: at A number of grouting pipes (9) are pre-pressed and arranged between the foundation pit retaining structure and the tower crane bearing platform (3); during the construction of the deep foundation pit, expansive cement slurry is pressurized and injected into the soil between the foundation pit retaining structure and the tower crane bearing platform (3) through the grouting pipes (9). By using the volume expansion generated during the hydration and hardening process of the expansive cement slurry, the horizontal and vertical displacements of the tower crane bearing platform (3) are actively compensated and controlled, achieving the purpose of actively controlling the horizontal displacement and settlement of the tower crane bearing platform.

4. The deep foundation pit side tower crane bearing platform reinforcement structure according to claim 1, characterized in that: A number of reinforcement anchor cables (11) are arranged outside the anchor tie pile connecting beam (10). On the exposed part of the reinforcement anchor cables (11) above the ground, there is a reinforcement anchor cable seat (12). A fixed pulley is rotatably arranged on the reinforcement anchor cable seat (12), and a bearing platform reinforcement steel wire rope (13) is arranged on the fixed pulley; on the anchor tie pile connecting beam (10) and the tower crane bearing platform (3), there are steel wire rope anchoring seats corresponding to the fixed pulley. The bearing platform reinforcement steel wire rope (13) bypasses the fixed pulley, and both ends are respectively connected to the steel wire rope anchoring seats on the anchor tie pile connecting beam (10) and the tower crane bearing platform (3); the bearing platform reinforcement steel wire rope (13) is applied with a pre-tension force through a core-piercing hydraulic lifter (16).

5. The deep foundation pit side tower crane bearing platform reinforcement structure according to claim 1, characterized in that: During the construction of the deep foundation pit, two rows of retaining structure reinforcement anchor cables (5) are successively arranged on the foundation pit retaining structure, reducing the deformation of the foundation pit retaining structure, and further reducing the horizontal displacement and vertical settlement of the tower crane bearing platform (3), preventing the problem of excessive deviation of the tower crane verticality.

6. The deep foundation pit side tower crane bearing platform reinforcement structure according to claim 3, characterized in that: The grouting pipe (9) includes an outer grouting pipe (9.1), an inner grouting pipe (9.2), and a spring (9.4); a number of grouting holes are arranged in an array on the outer walls of the outer grouting pipe (9.1) and the inner grouting pipe (9.2). The bottom of the outer grouting pipe (9.1) is provided with a closed cone head, and the bottom of the inner grouting pipe (9.2) is provided with a closed flat bottom; the inner grouting pipe (9.2) is movably arranged in the outer grouting pipe (9.1), and the spring (9.4) is arranged between the bottoms of the outer grouting pipe (9.1) and the inner grouting pipe (9.2); in the normal state, the grouting holes of the outer grouting pipe (9.1) and the grouting holes of the inner grouting pipe (9.2) are mutually misaligned. During grouting, the inner grouting pipe (9.2) compresses the spring (9.4), making the grouting holes of the outer grouting pipe (9.1) and the grouting holes of the inner grouting pipe (9.2) communicate with each other.

7. The deep foundation pit side tower crane bearing platform reinforcement structure according to claim 6, characterized in that: A limiting pin (9.3) is fixedly arranged near the lower part of the outer grouting pipe (9.1), and a limiting groove ( 9.2.2) is arranged on the flat bottom of the bottom of the inner grouting pipe (9.2). The limiting pin (9.3) is stuck in the limiting groove (9.2.2) to prevent the inner grouting pipe (9.2) from rotating in the outer grouting pipe (9.1).

8. A displacement control method for the deep foundation pit side tower crane bearing platform reinforcement structure according to any one of claims 3 and 7, characterized in that: During the construction of the deep foundation pit, the horizontal displacement and vertical displacement of the four monitoring points (17) on the upper part of the tower crane foundation (3) are detected at a set period, and the inclination of the tower crane is calculated; when the tower crane is inclined and the inclination is close to the preset required value, expansive cement slurry is pressure-injected into the soil between the foundation pit retaining structure and the tower crane foundation (3) through the grouting pipe (9). By using the volume expansion generated during the hydration and hardening process of the expansive cement slurry, the horizontal and vertical displacements generated by the tower crane foundation (3) are actively compensated, preventing the problem of excessive deviation of the tower crane verticality.

9. A displacement control method for the reinforcement structure of the tower crane foundation platform on the side of the deep foundation pit according to claim 4, characterized in that: During the construction of the deep foundation pit, the horizontal displacement and vertical displacement of the monitoring points (17) fixedly arranged at the four corners of the upper part of the tower crane foundation (3) are detected at a set period, and the inclination of the tower crane is calculated; when the tower crane is inclined and the inclination is close to the preset required value, the pretension of the foundation reinforcement steel wire rope (13) is increased through the core-piercing hydraulic lifter (16), and the horizontal and vertical displacements of the tower crane foundation (3) are actively compensated, preventing the problem of excessive deviation of the tower crane verticality.

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