Striding-type quick excavation method for down steps of surrounding rocks of grade IV-V of dual-track tunnel

Abstract

The invention provides a striding-type quick excavation method for down steps of surrounding rocks of a grade IV-V of dual-track tunnel and relates to the field of engineering construction. The methodsuccessively comprises the following steps: a down step blast area is divided into a left area and a right area which are symmetrical with an excavation center line of a working area face of a blasttunnel as the interface, shot holes are disposed on the left side of the excavation center line, and one-time drilling and in-place charging are carried out. One-time explosion initiation is carried out, and ventilation is carried out quickly after blasting; loading equipment and matched self-unloading equipment are carried out for quick tapping; danger elimination is carried out; an arc bridge isjointed in length, a roof truss frame is erected for each interval of a roof truss, a locking pin anchor tube is disposed, U-shaped rebar is used for welding reinforcement, and a reinforcement mesh is hung; and arc frames, locking pin anchor tubes, and mortar anchor rods are supplemented at empty places, casting is carried out on the locking pin anchor tubes and the system anchor rods, and sprayed concrete is constructed. The method disclosed by the invention can overcome defects in a conventional excavation method with a short single footage driving cycle. The method is simple, practical, economic and efficient in construction technologies, greatly increases the single footage drying cycle and shortens construction duration.

Description

technical field [0001] The invention relates to the field of engineering construction, in particular to a step-type rapid excavation method for double-track tunnels under the surrounding rocks of grades IV to V. Background technique [0002] The drilling and blasting method is a traditional tunnel construction method. The purpose of excavation is achieved by drilling a blasthole with a certain diameter and depth on the rock mass and loading it with explosives for blasting. Obviously, for medium and short tunnels and some long tunnels accounting for more than 50% of traffic tunnels, hydropower tunnel projects with large space and large diameter, and tunnel projects with non-circular cross-sections, the geological and hydrogeological conditions are extremely poor (such as many karst caves, many faults, Seepage, water gushing, debris flow, long-distance crushing zone) projects, the construction of drilling and blasting equipment has obvious application advantages. At present, ...

AI Technical Summary

Problems solved by technology

This method makes the footage per cycle of the lower bench very short, resulting in a very short average monthly excavation length of a single lower bench, which also affects the progress of the tunnel construction.

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