Safe construction method for ultra-shallow-buried excavation of large-section tunnel in urban core commercial district

Abstract

The invention relates to the technical field of tunnel construction, and discloses a safe construction method for an ultra-shallow-buried excavation large-section tunnel in an urban core commercial district, which comprises the following steps: excavating an ultra-shallow-buried section main channel by adopting a double-side-wall heading method; performing ground surface grouting reinforcement; a double-layer advanced small guide pipe is adopted for carrying out advanced support on a tunnel, and a steel trestle dispersing load face is laid. The method provided by the invention has little influence on the traffic of the existing traffic main road; vehicles on the road can run normally, so that road occupation and road closure as well as interference on normal functions of the urban core business district are avoided; optimization is carried out on the basis of a shallow-buried excavation method, so that the tunnel excavation safety is effectively improved, meanwhile, the construction sequence of all the procedures is optimized, all the procedures of the double-side-wall pilot tunnel are connected more tightly, the project management cost is reduced, and the construction progress is accelerated.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, and more particularly, to a safe construction method for ultra-shallow buried and large-section tunnels in urban core business circles. Background technique [0002] Shallow burial method is a method of underground excavation of various types of underground caverns near the surface. It mainly involves in the construction of tunnels in large cities, reducing the impact of the surface environment and buildings while ensuring the safe construction of tunnels. . The total length of the main passage tunnel of the third phase of the middle ring road of this project is about 498 cm. The tunnel is located directly below Linjiang Road. The thickness of the roof covering is 4.8 to 9.2 m. It is a shallow buried large-section tunnel with poor surrounding rock conditions. Underground, close to Hongyadong Scenic Area, Linjiang Road above the tunnel is densely populated with people and vehicles, su...

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Problems solved by technology

[0003] The shallow burial and underground excavation method is based on most of the principles of the "New Austrian Method", guided by "pipe advance, strict grouting, short excavation, strong support, fast closure, frequent measurement", and is applied in the construction process Monitoring and measurement, information feedback and optimized design to achieve no landslides, less settlement, and safe construction. However, this method is not safe for project progress and road surface settlement in complex urban core business districts with ultra-shallow buried soil and mainly backfill soil. It is difficult to guarantee the safety, as the main arterial road in the core business district of the city, it cannot be closed for construction, and the construction cost is huge

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