Shield launching method for soft earth layer

Abstract

The invention discloses a shield launching method for a soft earth layer. An earth pressure balance shield machine is used for directly excavating and cutting a well wall to enter a well, a certain amount of filler is injected into an earth bin in advance before a cutter head of the earth pressure balance shield machine advances in front of an excavation surface, the active earth pressure is built up inside the earth bin to enable the pressure inside the earth bin to be balanced with the earth layer pressure of the excavation surface, conditions for earth pressure balance tunneling are satisfied, the disturbance to a stratum is reduced during construction, water and earth losses are prevented, ground collapse is avoided, and safe launching is realized. The method comprises the steps as follows: 1) the geology of a launching section is measured; 2) specific parameters of pressure buildup of the launching earth bin are determined, and the earth layer of the excavation surface is reinforced; 3) the filler is injected to build up the pressure; 4) the pressure of the earth bin and ground surface bulges and pits are monitored; and 5) the shield machine excavates, cuts and launches directly. The shield launching method is full-automatic and convenient to operate, short in construction time, high in efficiency, low in capital investment and capable of ensuring the construction timeliness and satisfying policy construction demands.

Description

technical field [0001] The patent of the present invention relates to the technical field of shield tunneling, in particular to a shield tunneling method for weak soil layers. Background technique [0002] With the development of society and the development of underground space, shield tunneling technology has been widely used in engineering fields such as subways, tunnels, and municipal pipelines due to its high degree of mechanization, low labor intensity, safety and speed, and many other advantages. In recent years, due to the relative maturity of the shield tunneling technology, the station has been greatly raised due to cost considerations, which brings more challenges to the shield tunneling launch. [0003] Before the start of the shield tunneling, the enclosure structure of the station needs to be chiseled out, and the soil after the excavation of the enclosure structure must maintain self-stabilization within a certain period of time, which makes the construction of...

AI Technical Summary

Problems solved by technology

During the construction of shield tunnels in weak ground, at the initial stage of the shield machine, the cutter head just enters the soil layer to break the rock, and the stress of the soil body is released instantly, and the soil bunker is excavated from the empty bunker to establish active earth pressure to balance the water and soil Passive pressure still needs a process, but when the shield machine is excavating in the initial stage, due to the large space between the soil bin and the screw machine, the stress of the soil is released to release the space, which can easily cause the soil to be "unstable". A large number of sand and water gushes appear, affecting the starting quality, and serious cases may cause the shield machine to be buried

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