Soft rock four-line large-span tunnel compound double-side wall bracing cable conversion excavation construction method

Abstract

The invention relates to a soft rock four-line large-span tunnel compound double-side wall bracing cable conversion excavation construction method which has the characteristics of safety in construction, speediness and simpleness in operation, and is further applicable to large-scale machines for construction. The method comprises the following steps: (1) excavating pilot holes on side walls on two sides, firstly implementing corresponding forepoling before excavation, and immediately implementing corresponding preliminary bracing and temporary bracing after the excavation; (2) pouring pedestal foundations on the two sides; (3) excavating side pilot holes of arch parts on the two sides respectively, firstly implementing the corresponding forepoling before the excavation, immediately implementing the corresponding preliminary bracing and the temporary bracing after the excavation, and implementing a pre-stressed anchor cable connected with a surrounding rock anchor at the top of the corresponding preliminary bracing; (4) excavating core soil of the arch parts bench by bench, firstly implementing the corresponding forepoling before excavating an upper bench, immediately implementing the corresponding preliminary bracing after the excavation, and implementing the pre-stressed anchor cables connected with the surrounding rock anchor at two end parts of the preliminary bracing; (5) pouring secondary lining of the arch parts; (6) excavating the lower core coil bench by bench; and (7) pouring an inverted arch, and pouring the inverted arch to the design height.

Description

technical field [0001] The invention relates to a railway tunnel excavation construction method, in particular to a soft rock four-line long-span tunnel composite double-side wall support cable conversion excavation construction method. Background technique [0002] After entering the 21st century, my country's railway construction has developed rapidly. With the rapid and large-scale construction of high-speed railways in the southwest mountainous areas, due to the constraints of various factors such as large curve radius, complex terrain and geological conditions, and high environmental protection requirements, some sections along the railway line have been designed. The station conditions are extremely difficult. Therefore, in order to improve the freedom of route selection and station establishment for building high-speed railways in difficult and dangerous mountainous areas, make the layout of mountainous stations more flexible, and ensure station functions more easily, ...

AI Technical Summary

Problems solved by technology

For four-line long-span tunnels with a span of 20-30m, when the surrounding rock formations are mainly soft (mass) rock formations such as mudstone, argillaceous sandstone and sandy mudstone, it is very difficult to adopt the above excavation construction method, and there are temporary supports There are many problems, the distance of dismantling is limited, the surrounding rock is easily deformed, unstable, and the construction operation is inconvenient. The construction safety and the progress of the construction period will not be guaranteed.

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