Pile strengthening system with MJS construction method for under-crossing existing tunnel in water-rich sand layer shielding and construction method

Abstract

The invention provides an MJS method pile reinforcement system and a construction method in the field of urban subway tunnel construction technology in which a water-rich sand layer shield passes under an existing tunnel. The main construction steps of this kind of reinforcement system are: (a) investigation of the safety status of the operating tunnel segment, (b) the layout of the monitoring system in the tunnel; (c) the construction of the shaft; (d) the reinforcement construction of the MJS horizontal pile; (e) the detection of the reinforcement effect ; (f) Shaft landfill. This method reinforces the water-rich sand layer between the proposed tunnel and the operating tunnel by constructing MJS horizontal piles in the vertical shaft, and inspects it after the construction is completed to ensure the reinforcement effect, thus reducing the impact on the shield tunneling process of the proposed tunnel. The impact of the upper part of the tunnel in operation has enabled the tunnel shield excavation and underpass work to proceed smoothly.

Description

technical field [0001] The invention relates to the technical field of urban tunnel construction, in particular to an MJS construction method pile reinforcement system and a construction method for a shield passing through an existing tunnel under a water-rich sand layer. Background technique [0002] In recent years, with the continuous improvement of my country's urbanization level, the demand for urban rail transit is increasing, and urban rail construction technology has developed rapidly. In the current track construction technology, shield machines are usually used for tunnel excavation. However, the planning of urban rail lines will inevitably lead to the underpass of existing tunnels. If the construction is not done properly, it will lead to additional stress and differential settlement of the upper operating tunnels. . In the current construction technology, ground grouting is usually used for reinforcement to reduce the impact of the shield tunneling construction ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to carry out tunnel shield excavation construction in the water-rich sand layer. When there is an operational tunnel above the construction tunnel and ground grouting is used for reinforcement, due to the large void ratio of the water-rich sand layer and poor grouting quality, it cannot Effectively stop water and support the weight of the soil itself, resulting in differential deformation and excessive additional stress of the upper tunnel in operation, serious damage to the segments, and the construction strength of the ground grouting reinforcement is high, and there is a lot of waste in the project. Provide a water-rich solution MJS engineering method pile reinforcement system and construction method of the existing tunnel under the sand layer shield. This method reinforces the soil between the intersecting tunnels by constructing MJS horizontal piles in the vertical shaft, and inspects the soil after the construction is completed to ensure the reinforcement In the process of tunnel shield excavation, problems such as excessive settlement and deformation of the upper part of the tunnel in operation and serious damage to segments can be avoided

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