Construction method for traversing shallow water-enriched sand layer by composite soil pressure balanced shield tunneling machine

Abstract

The invention discloses a construction method for a composite earth pressure balance shield machine to pass through a shallow buried water-rich sand layer, and belongs to the technical field of tunnel construction. When the composite earth pressure balance shield machine passes through the shallow buried water-rich sand layer, the injection system is installed at the pressure plate and cutter head of the shield machine to inject into the front shallow buried water-rich sand layer. Performance substances—foaming agents, or bentonite, or high molecular polymers, or their mixtures; rapidly expand the shallow water-rich sand layer, make the soil entering the full pressure chamber into a plastic flow state, and Make the soil meet the requirements of the permeability coefficient of less than 10-5cm / s and the slump of 10-15cm required for construction. The technical scheme of the invention is scientific and reasonable, simple and easy to implement, and the obtained technical effect is remarkable.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a special construction method for a composite earth pressure balance shield machine suitable for construction on a relatively solid rock layer when crossing a shallow buried water-rich sand layer. Background technique [0002] Composite earth pressure balance shield machine is mainly suitable for relatively strong composite strata, and can be constructed in earth pressure balance mode, semi earth pressure mode, and empty warehouse mode. It not only has fast construction speed, but also has low wear on the tool. During the tunnel construction of the applicant on Guangzhou Rail Transit Line 6, 86% of the total length of the tunnel is composed of strongly weathered, moderately weathered and lightly weathered rocks, and it is more reasonable to adopt the composite earth pressure balance mode shield machine. However, there is a 350m-long water-rich sand layer b...

AI Technical Summary

Problems solved by technology

[0004] (1) Due to the high permeability of the silt-fine sand stratum and medium-coarse sand stratum, and the construction section is close to the Pearl River, the groundwater is abundant and the pressure is high, and problems such as gushing are prone to occur during construction, resulting in the rapid disappearance of support pressure, resulting in surface subsidence. Seriously affect ground traffic, buildings and personnel safety;

[0005] (2) If the dregs are not improved properly, they will be compacted under high pressure, and there may be construction failures such as poor soil discharge, blocked soil bins and screw machines

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