Reinforcing method for shallow covering shield tunnel based on soft ground

Abstract

The invention discloses a reinforcing method for a shallow covering shield tunnel based on soft ground. The method comprises the following steps: S1, reinforcing the ground by using triple-tube high-pressure jet-grouted piles at parts which are 2m to the top, bottom, left and right of the cross section of the tunnel; and S2, carrying out reinforcing in the tunnel, carrying out shield excavation inshallow covering ground by adopting a segment with more grouting holes, adopting an earth pressure balance shield excavation mode, ensuring sufficient synchronous grouting, timely carrying out secondary double-liquid grout injection after the segment drops out of the tail of a shield so as to further improve the stability of the segment, and adopting a hollow grouting anchor rod to carry out deep-hole grouting reinforcing on the tunnel along lifting holes and the grouting holes after the segment drops out of an equipment bridge section behind the tail of the shield or the segment drops out ofthe rear part of a trolley. The reinforcing method for the shallow covering shield tunnel based on the soft ground can solve the floating problem of forming the shield tunnel in the soft shallow covering ground and guarantee the safe running of a subway train.

Description

technical field [0001] The invention belongs to the technical field of shield tunneling, and in particular relates to a reinforcement method for a shallow-covered soil shield tunnel based on weak ground. Background technique [0002] Shield construction has become the main construction method of urban rail transit construction. With the rapid development of urban rail transit, shield tunnel construction often passes through various complex strata, including water-rich composite strata and water-rich karst strata, both of which exceed 20m The above deep overburden also has shallow overburden less than the radius of the tunnel. Different hydrogeological conditions have different requirements on the stability of formed tunnels. [0003] In the construction of the city's emerging CBD, there are many joint construction problems of rail transit, underground space, and comprehensive pipe gallery. When passing through the underground space or comprehensive pipe gallery structure un...

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Problems solved by technology

[0003] In the construction of the city's emerging CBD, there are many joint construction problems of rail transit, underground space, and comprehensive pipe gallery. When passing through the underground space or comprehensive pipe gallery structure under the shield, the problem of shallow covering soil is often encountered. Shield tunnels Changes in the thickness of the covering soil will affect the stability of the tunnel. In the water-rich stratum, problems such as tunnel displacement and water leakage caused by the uplift of the formed tunnel are prone to occur; The excavation of the corridor has resulted in the reduction of the covering soil of the formed shield tunnel, and the change of the covering soil has brought the risk of the tunnel floating; the floating of the formed shield tunnel has brought the risk of the normal operation of the subway train, and the shield tunnel in operation has been carried out. Reinforcement treatment will affect the normal operation of subway trains and there is a greater construction safety risk

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