Moisture rich and weak mylonite large section tunnel surrounding rock consolidation and excavation method

Abstract

The invention relates to a moisture rich and weak mylonite large section tunnel surrounding rock consolidation and excavation method. The moisture rich and weak mylonite large section tunnel surrounding rock consolidation and excavation method includes the following steps that before excavation, a wall for grouting is constructed on the upper half section of a tunnel face; after the strength of the wall of the grouting is stable, injected holes are distributed; grouting is conducted through a high-pressure, splitting and compaction grouting method, and final grouting pressure is not less than 4MPa; after the grouting is completed, all excavation portions are respectively provided with a access hole, and cores are taken to test the grouting effect; after the test result is up to the standards, the wall for grouting is broken, and the excavation is started; after the excavation is finished, the next circle from the step one to the step five is started until the whole tunnel excavation is finished. The moisture rich and weak mylonite large section tunnel surrounding rock consolidation and excavation method has the advantages that aiming at a moisture rich and weak mylonite large section tunnel, advanced reinforcement of surrounding rock can be effectively achieved. Under the condition of VI-level surrounding rock, large section advancing excavation is achieved, and the disadvantageous factors that in the past, through a double-side drift method and a CRD method, using of large machinery is limited, the number of temporary supports is large, construction disturbance in each working procedure is large are overcome.

Description

technical field [0001] The invention relates to the technical field of tunnel reinforcement and excavation, in particular to a method for reinforcement and excavation of surrounding rock of a large-section tunnel with rich water and weak mylonite. Background technique [0002] Mylonite is a fault rock formed under ductile deformation conditions, which is composed of matrix and broken plaques. Mylonite is a rock formed by strong crushing and plastic deformation. It is often distributed on both sides of the fault zone. Due to the action of compressive torsional stress, the rocks are dislocated and the particles are broken. Due to the composition and structure characteristics of mylonite itself, it is extremely sensitive to water, and it is difficult to strengthen it by conventional infiltration grouting. After the excavation of the tunnel, the strength index of the surrounding rock of mylonite drops rapidly under the action of water seepage and excavation disturbance, and the...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a method for strengthening and excavating the surrounding rock of a large-section tunnel with rich water and weak mylonite, so as to overcome the above-mentioned deficiencies in the current prior art

Images