Low-clearance and short-distance obstacle removing construction method for existing operation station enclosure structure

Abstract

The invention discloses a low-clearance and close-range barrier removal construction method for an existing operation station enclosure structure, which comprises the following steps: S1, underground diaphragm wall construction: S11, underground diaphragm wall groove wall reinforcement: according to the stratum condition, in order to avoid hole collapse in the groove forming process, adopting MJS construction method piles for reinforcement treatment between a barrier removal working well and new and old ground walls of a station, and S12, construction of an underground diaphragm wall; grooving the underground diaphragm wall; s13, hoisting an underground diaphragm wall reinforcement cage; s14, concrete pouring is conducted; s2, crown beam supporting and dewatering well construction; s3, foundation pit excavation and support erection construction are carried out; s4, constructing a lining wall; s5, freezing construction is conducted; s6, barrier removal construction is carried out; and S7, backfilling construction is conducted. The problem that conventional construction cannot meet the construction requirements that the obstacle removing working well is located in a low clearance, adjacent to an operation subway line and a bridge pile and small in space of the obstacle removing working well is solved, obstacle removing work can be safely completed, and operation of the subway line and the viaduct cannot be affected.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering, and more particularly to a construction method for removing obstacles from the retaining structure of an existing operating station with low headroom and close proximity. Background Art

[0002] The Chinese utility model patent with the publication number CN214062954U discloses a construction system for a shield tunneling through obstacles under an operating station, characterized in that the construction system includes obstacle removal working wells arranged on both sides of an existing subway station and a frozen soil curtain located under the existing subway station, the depth of the frozen soil curtain is not less than the depth of the obstacle removal working wells, and a support cross beam is arranged in the obstacle removal working wells. The advantages of this utility model are: the construction system has a simple structure, can solve the defect that existing shield equipment does not have the ability to cut large-volume and high-strength obstacles; ensure the effective removal of all obstacles within the shield tunneling section, creating conditions for the smooth passage of the shield; minimize the impact on the existing operating station to the greatest extent, providing reference for similar projects.

[0003] However, the construction system for obstacles under the operating station of the above patent belongs to conventional practices. Although it can meet the construction of general obstacle removal working wells, it cannot meet the construction requirements of obstacle removal working wells with low headroom, close proximity to the operating subway station, bridge piles, and narrow space of the obstacle removal working wells themselves. Therefore, there is an urgent need to provide a construction method for removing obstacles from the retaining structure of an existing operating station with low headroom and close proximity. Summary of the Invention

[0004] In view of this, the present invention provides a construction method for removing obstacles from the retaining structure of an existing operating station with low headroom and close proximity, aiming to solve the problems existing in the prior art.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A construction method for removing obstacles from the retaining structure of an existing operating station with low headroom and close proximity, comprising the following steps:

[0007] S1, construction of diaphragm walls, specifically including: S11, reinforcement of diaphragm wall trench walls. According to the formation conditions, in order to avoid collapse of the trench during the trenching process, MJS method piles are used for reinforcement treatment between the obstacle removal working wells and the new and old diaphragm walls of the station; S12, trenching of diaphragm walls; S13, hoisting of diaphragm wall steel cages; S14, concrete pouring;

[0008] S2, construction of capping beams and dewatering wells;

[0009] S3, construction of foundation pit excavation and support erection;

[0010] S4, construction of inner lining walls;

[0011] S5, Freezing construction;

[0012] S6, Obstacle removal construction;

[0013] S7, Backfilling construction.

[0014] Preferably, in the S11, the diameter of the MJS method pile is 3.2m.

[0015] Preferably, in the S12, horizontal double-wheel milling is used for grooving.

[0016] Preferably, in the S13, according to the clearance under the bridge and the actual space and position on site, the steel reinforcement cage is hoisted in sections by a gantry crane and lowered for construction.

[0017] Preferably, in the S3, a micro-excavator, a gantry crane and a muck bucket are used for construction.

[0018] Preferably, before freezing construction, according to the space of the obstacle removal working well, the freezing pipes are driven at 1.5m per section, and the freezing pipes are connected by screw threads and welding.

[0019] The present invention has achieved the following technical effects compared with the prior art:

[0020] 1) The present invention solves the problem that conventional construction cannot meet the construction requirements of the obstacle removal working well located in a low clearance, adjacent to an operating subway line, bridge piles and the small space of the obstacle removal working well itself, and can safely complete the obstacle removal work without affecting the operation of the subway line and the viaduct, providing a reference basis for the subsequent shield tunneling through the existing diaphragm wall of the station under limited conditions for obstacle removal construction;

[0021] 2) The present invention improves the operation efficiency and reduces the labor intensity of the operation;

[0022] 3) By optimizing the construction sequence, the present invention improves the construction efficiency, shortens the construction period and saves the construction cost. Description of the Drawings

[0023] Figure 1 It is a flow chart of a construction method for removing obstacles from the retaining structure of an existing operating station with low clearance and short distance;

[0024] Figure 2 It is a construction schematic diagram of the MJS method pile;

[0025] Figure 3 It is a construction schematic diagram of the diaphragm wall grooving;

[0026] Figure 4 It is a steel reinforcement cage hoisting schematic diagram;

[0027] Figure 5 It is a freezing hole construction schematic diagram. Detailed implementation manners

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] Embodiment

[0030] The present invention discloses a construction method for removing obstacles from the retaining structure of an existing operating station with low headroom and short distance, including the following steps:

[0031] S1. Diaphragm wall construction, specifically including: S11. Diaphragm wall trench wall reinforcement. According to the formation conditions, MJS method piles are used for reinforcement treatment between the obstacle removal working well and the new and old diaphragm walls of the station, with a depth of 36 m. Pilot hole construction is carried out to prevent the collapse of the diaphragm wall trench of the obstacle removal working well and reduce the impact on the station. S12. Diaphragm wall trench excavation; S13. Hoisting of the diaphragm wall steel cage; S14. Concrete pouring;

[0032] S2. Construction of the capping beam support and dewatering wells;

[0033] S3. Foundation pit excavation and support erection construction;

[0034] S4. Inner lining wall construction;

[0035] S5. Freezing construction;

[0036] S6. Obstacle removal construction;

[0037] S7. Backfilling construction.

[0038] In this embodiment, in S11, the diameter of the MJS method pile is 3.2 m.

[0039] In this embodiment, in S12, the construction space of the obstacle removal working well is very small. Since the diaphragm wall of the obstacle removal working well enters the rock, the horizontal double-wheel milling method is used for diaphragm wall trench excavation.

[0040] In this embodiment, in S13, according to the under-bridge headroom, the actual on-site space and position, the steel cage is hoisted and lowered in sections by a gantry crane; specifically, the gantry crane in S13 is a customized 80t gantry crane.

[0041] In this embodiment, the steel cage is integrally processed and hoisted in sections, and the joints are connected by mechanical methods and assisted by steel plate welding.

[0042] In this embodiment, in S3, the foundation pit excavation is carried out by using a mini excavator, a gantry crane and a muck bucket; specifically, the gantry crane in S3 is a customized 8t gantry crane.

[0043] In this embodiment, the erection and demolition of the support are carried out by using a customized gantry crane.

[0044] In this embodiment, before the freezing construction, according to the space of the obstacle removal working shaft (the space is small, and the freezing pipes are arranged almost parallel to the inner lining wall), the freezing pipes are driven at a length of 1.5m per section. The positions of the freezing pipes are located by a total station. After the freezing pipes are connected by screw threads, they are then connected by welding.

[0045] In this embodiment, the freezing holes are constructed by using drill pipes with a diameter of 89mm, and inclined holes are used at the corners.

[0046] The above technical solution aims at the narrow space of the obstacle removal working shaft itself. Some of the freezing pipes are drilled almost parallel to the wall surface. The freezing pipes are arranged at a length of 1.5m per section. The joints are connected by screw threads and outer ring welding, and the angle of each hole is controlled to ensure the layout accuracy of the freezing pipes.

[0047] In this embodiment, the diaphragm wall reinforcement must meet the requirements that the unconfined compressive strength for 28 days is not less than 1.5 Mpa and the anti-seepage coefficient is less than or equal to 1×10 -7 cm / s.

[0048] In this embodiment, the verticality during the trench excavation process is not greater than 1 / 300.

[0049] The above is only a preferred embodiment of the present invention, and does not impose any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for removing obstacles from existing operating station enclosure structures at low headroom and close distance, characterized in that: The following steps are involved: S1, underground continuous wall construction, specifically including: S11, underground continuous wall trench wall reinforcement, according to the stratum conditions, in order to avoid the hole collapse during the trenching process, MJS pile reinforcement treatment is used between the obstacle clearance work well and the new and old ground walls of the station, S12, underground continuous wall trenching; S13, underground continuous wall steel cage hoisting; S14, concrete pouring; S2, crown beam support and dewatering well construction; S3, foundation pit excavation and support installation; S4, lining wall construction; S5, construction freeze; S6, obstacle removal construction; S7, backfill construction.

2. According to claim 1, a low-headroom, close-range existing operating station enclosure structure obstacle removal construction method is characterized in that: In the S11, the diameter of the MJS method pile is 3.2 m.

3. According to claim 1, a low-headroom, close-range existing operating station enclosure structure obstacle removal construction method is characterized in that: In the step S12, horizontal double-wheel milling is used to form the grooves.

4. According to claim 1, a low-headroom, close-range existing operating station enclosure structure obstacle removal construction method is characterized in that: In S13, according to the clearance under the bridge and the actual space and position on site, a gantry crane is used to hoist the steel cage in sections for lowering construction.

5. According to claim 1, a low-headroom, close-range existing operating station enclosure structure obstacle removal construction method is characterized in that: In S3, a micro excavator, a gantry crane and a slag bucket are used for construction.

6. The method for removing obstacles from existing operating station enclosure structures at low headroom and close distance according to claim 1 is characterized in that: Before freezing construction, freezing pipes are laid at 1.5m sections according to the space of the clearance work pit, and the freezing pipes are connected by threading and welding.

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