Construction method for leading out turnout extra-large-section tunnel in railway cave

Abstract

The invention discloses a construction method for leading out a turnout extra-large-section tunnel in a railway cave. The construction method comprises the following steps that 1, an extra-large-section cave auxiliary excavation section is constructed; 2, expanding excavation is conducted on the auxiliary excavation section; 3, grouting is conducted on a middle pipe shed; and 4, the extra-large-section cave is excavated. According to the construction method for leading out the turnout extra-large-section tunnel in the railway cave, construction is flexible and changeable, the applicability is high, and the construction speed is high; by combining the characteristic that the lithology of surrounding rock of the extra-large-section cave is good, a simple middle partition wall method and two large-diameter steel pipe temporary vertical supports are adopted on the upper half section of the extra-large-section cave, and excavation is conducted on the lower half section of the extra-large-section cave through a step method; a double-side-wall equal-large-section shallow-buried and soft rock construction method is replaced, so that a steel arch frame can be smoothly connected from the arch top to the two ends, the stress structure is stable, and enough operation space can be provided for large construction operation equipment; and the defects that according to the double-side-wall equal-large-section shallow-buried and soft rock tunnel excavation construction method, large equipment is difficult to unfold, the construction speed is low, and the safety risk is high are overcome, and the application range of the tunnel step method excavation construction method is expanded.

Description

technical field [0001] The invention belongs to the technical field of tunnel engineering construction, and in particular relates to a construction method for a super-large-section tunnel leading out of a branch line in a railway tunnel. Background technique [0002] With the large-scale construction of high-speed railways and expressways in my country, there are more and more long-span tunnels. Tunnel construction in some areas, such as Chongqing Mountain City, is affected by terrain conditions. Sometimes stations or branch lines have to be set in tunnels to form station or lead-out branch line tunnels, and the span of the tunnel section increases sharply. [0003] The construction technology of extra-large cross-section tunnels at home and abroad is becoming more and more mature. The excavation methods mainly include the cross middle partition (CRD) method, the double side wall pilot pit method (spectacles method), the middle hole method, and the hole pile method. The con...

AI Technical Summary

Problems solved by technology

Based on this kind of deep-buried super-large-section tunnel with good surrounding rock lithology and complete rock strata, the above excavation methods are not very pertinent, and further research is needed to explore new construction methods

Images