Double-side Pilot Excavation Method for Tunnel Excavation

Abstract

The application provides a double-side pilot pit type excavation method for tunnel excavation, which includes the following steps: (1) dividing the tunnel section into pilot pit excavation area, core soil excavation area and tunnel bottom excavation (2) In the case of advanced support, excavate the excavation area of ​​the pilot pit; (3) In the case of advanced support of the side wall of the pilot pit and the main tunnel, excavate the core in stages from the top of the tunnel to the bottom of the tunnel (4) Excavate the excavation area at the bottom of the tunnel, and erect support to form a ring with the existing support; (5) Remove the temporary support and pour the main tunnel invert; (6) Lay waterproof boards, using The formwork trolley is used for secondary lining; (7) Repeat the above steps until the tunnel is penetrated. The pilot pit excavation area is constructed before the core soil excavation area, and the soil in the core soil excavation area is used as support to reduce the longitudinal thrust of the tunnel face soil and prevent the collapse of the surrounding rock vault, effectively reducing tunnel The sinking of the primary support vault and the convergence of the headroom level ensure construction safety.

Description

technical field [0001] The present application relates to the field of railway tunnel construction, in particular to a double-side pilot-pit excavation method for tunnel excavation. Background technique [0002] In recent years, my country's urban railways have developed rapidly, and the number and mileage of construction have increased year by year, and great achievements have been made. However, shallow-buried and underground excavated large-section gradient tunnels for urban railways have large spans and complex construction procedures. It is difficult to mass-produce the initial support of the gradient section, and the construction efficiency is low, which seriously affects the construction progress, especially in weak surrounding rocks. Surface subsidence and The horizontal displacement of the gradient section is difficult to control, and the construction is extremely difficult. Shallow-buried and underground excavated large-section gradient tunnels for urban subways, ...

AI Technical Summary

Problems solved by technology

However, shallow-buried and underground excavated large-section gradient tunnels for urban railways have large spans and complex construction procedures. It is difficult to mass-produce the initial support of the gradient section, and the construction efficiency is low, which seriously affects the construction progress, especially in weak surrounding rocks. Surface subsidence and The horizontal displacement of the gradient section is difficult to control, and the construction is extremely difficult

Shallow-buried and underground excavated large-section gradient tunnels for urban subways, especially V-level shallow buried sections, soil surrounding rock ends, or entrance sections with severe weathering and fracture (S-Va), have poor strength and stability, and are prone to collapse during excavation

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