Method and system for jacking open-cut box culverts across operating subway interval

Abstract

The invention discloses a method and system for jacking open-cut box culverts across an operating subway interval. The method comprises the following steps that formation system reinforcement is performed on existing tunnels, the a box culvert jacking foundation pit is manufactured, and the box culverts are prefabricated in the foundation pit; foundation pit retaining piles in the jacking direction of the box culverts are cut, a soil mass within the jacking range of the box culverts is excavated by an open-cut method, and the box culverts are jacked in at the same time; the multi-section box culverts are sequentially jacked in, and post-casting belt construction is carried out between the adjacent jacked box culverts; and when the box culverts are jacked in, jacks are symmetrically arranged on both sides of the box culvert jacking direction, the two jacks are symmetrically jacked into the box culverts, and the thrust of the two jacks is corrected by a thrust control device. The impacton operating subways can be reduced, the jacking of the box culverts is facilitated, and the defect of deformation of an operating subway structure caused by foundation pit excavation is overcome.

Description

technical field [0001] The invention relates to the technical field of building tunnel engineering construction, in particular to an open-cut box culvert jacking method and system across an operating subway section. Background technique [0002] With the rapid development of my country's subway construction, the close proximity of old and new buildings in a limited urban space makes the underground engineering environment more and more complicated. There are more and more foundation pit projects across the existing subway tunnels, including cross-street tunnel projects and underground highway projects. , Building basement foundation pit engineering, etc. When the new structure is close to the subway tunnel, the design should not only consider the safety of the new structure, but also protect the normal operation of the existing subway tunnel. Due to the shallow buried depth of the subway tunnel, the increase and decrease of the overlying pressure will disturb the stratum whe...

AI Technical Summary

Problems solved by technology

When the new structure is close to the subway tunnel, the design should not only consider the safety of the new structure, but also protect the normal operation of the existing subway tunnel; excavation of the foundation pit will cause soil unloading, resulting in uplift of the soil at the bottom of the foundation pit and soil behind the wall Due to the shallow burial depth of the subway tunnel, the increase and decrease of the overlying pressure will disturb the stratum where the tunnel is located, which will affect or even change the stress-strain state of the subway tunnel below it, resulting in Vertical and horizontal displacement, and at the same time, the cross-section will also produce convergent deformation. In serious cases, there will be safety hazards such as tunnel segment fracturing and joint water seepage

In addition, soil disturbance at the bottom of the pit, reinforcement of the underground diaphragm wall or pile foundation, and dewatering of the foundation pit will also affect the safety of the tunnel.

[0003] The traditional pipe curtain box culvert jacking method forms an underground excavation similar to a tunnel, which cannot realize the operation of digging and jacking at the same time, which makes it easy to eat soil during the box culvert jacking process, and also requires other auxiliary operations, such as palming. Grouting for subsurface soil reinforcement and excavation of muck in the tunnel not only increase the excavation cost of the foundation pit, but also because the four sides are not fixed during excavation, the elevation adjustment needs to be adjusted up, down, left, and right, which increases the cost of manpower and material resources. The soil eating during the culvert jacking process also made it difficult to adjust the upper and lower elevations

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