Shield tunnel construction and reinforcement method for underneath passing through existing tunnel in upper-soft and lower-hard stratum

Abstract

The invention discloses a shield tunnel construction and reinforcement method for underneath passing through an existing tunnel. The shield tunnel construction and reinforcement method comprises the following steps of that before underneath passing through the existing tunnel in the shield construction of a first newly-built tunnel, a plurality of first directional drill holes distributed side byside are drilled and first grouting pipes are inserted at the position, corresponding to the outer side of the existing tunnel, of the ground surface; and pressure grouting is conducted on a first to-be-reinforced stratum located between a to-be-penetrated area of the first newly-built tunnel and the existing tunnel on the ground surface through the first grouting pipes, grout flows out through grout outlets in the peripheral walls of the first grouting pipes and permeates into a soft soil body of the first to-be-reinforced stratum, and the soft soil body can be bonded into a whole after solidification. A first reinforced area within a certain range is formed between the first newly-built tunnel and the existing tunnel, meanwhile, the multiple first grouting pipes buried in the stratum further play a pipe shed supporting role and jointly form a supporting system, a local supporting barrier is formed between the first newly-built tunnel and the existing tunnel, and the self-stabilization strength and the disturbance resistance of the first reinforced area are improved.

Description

technical field [0001] The invention relates to the technical field of tunnel engineering, in particular to a shield tunnel construction method and a local reinforcement method for passing through an existing tunnel at a short distance in an upper soft and lower hard stratum. Background technique [0002] In South China, especially in the Pearl River Delta region, there are a large number of upper soft and lower hard strata. In some parts, this uneven stratum distribution will cause local mutations. For the construction of shield tunnels, the shield machine needs to adjust the tunneling mode and parameters in time during the excavation process of the upper soft and lower hard strata to ensure construction efficiency and safety. [0003] With the development of urban rail transit, in the construction process of new tunnels (such as new subway tunnels), there are more and more cases of passing through existing tunnels (such as existing subway tunnels) at close range. When sho...

AI Technical Summary

Problems solved by technology

However, in the construction of passing through the existing tunnel, the existing tunnel is in uninterrupted operation, which brings difficulties to the application of the existing tunnel space to strengthen the ground; while the existing ground vertical grouting reinforcement is difficult to directly apply to the new tunnel and the existing tunnel. The soil between the tunnels is reinforced and an effective reinforcement zone is formed

In addition, the air tightness of the soft ground is poor, and it is difficult for the shield machine to adopt the air pressure-assisted tunneling mode, which is not conducive to reducing parameters such as cutter head torque, and is easy to form mud cakes, which affects construction efficiency and construction safety.

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