Large loose rock pile support arch tunnel-entering method

Abstract

A large loose rock pile support arch tunnel-entering method comprises the steps that S1, a side slope is subjected to early pretreatment; S2, a 3m support arch body serving as a guiding wall is constructed in the mode of being close to the slope; S3, after concrete in the guiding wall reaches strength, 43 m supporting steel pipes are constructed in a plurality of guiding steel pipes in the step S2, thus an advance large pipe shed is formed, and the supporting steel pipes are grouted to cement the large pipe shed and a rock pile; S4, after grouting of the large pipe shed is completed, a residual 10 m support arch body starts to be constructed towards the outer side; and S5, after construction of a 13 m support arch is completed, an entering tunnel starts to be excavated underground from theends of the support arch for timely initial supporting. The support arch is constructed at an open excavation section of a tunnel firstly, and then open cut tunnel underground excavation is constructed, so that not only is the excavation amount of the rock pile decreased greatly, but also disturbance of engineering construction to the rock pile is reduced effectively.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a method for entering a tunnel with a protective arch of a giant loose rock pile. Background technique [0002] The scale of the rock piles at the entrance of the Daqian Shiling Tunnel is extremely large. The rock piles cover almost the entire mountain at the entrance of the tunnel. The natural slope is 26°-38°, and the thickness of the rock piles is 26.3-48.4 meters. in the river. The rock piles are mainly composed of rocks of different sizes, the rock is the quartz sandstone of the Diaoyutai Formation (Z1d) in the Early Sinian system, and the diameter of the rocks is mostly between 0.5m and 1.5m, and the larger ones are 2 to 3m. Uniform, loose overhead structure, basically no bonding, no broken stones and fine-grained soil filling, no sorting, the porosity of the rock pile reaches 40%-50%. [0003] The Daqian Shiling Tunnel passes through the middle and upper part...

AI Technical Summary

Problems solved by technology

In the first 29.5m, the terrain is relatively gentle, and it is easier to implement open-hole excavation combined with construction needs, but the remaining 13m, the terrain is very steep, and a large-scale grading is required for open-hole excavation. It will cause great disturbance to the rock piles that are currently in a self-stable state, and there will be great safety hazards. Once a slide occurs, it will be very difficult to remediate

Images