Extremely-high geostress soft rock large-deformation tunnel multistage pressure-yielding and pressure-resisting support structure and construction method thereof

Abstract

The invention relates to an extremely-high geostress soft rock large-deformation tunnel multistage pressure-yielding and pressure-resisting support structure and a construction method thereof. The construction method comprises the following steps: excavating a tunnel with a nearly circular section, then driving long anchor cables and short anchor rods into surrounding rock, erecting ring-shaped profile steel frames at tail ends of the long anchor cables and the short anchor rods and spraying concrete, additionally driving reinforcement lengthened or encrypted anchor cables into the surroundingrock, then erecting steel frames and spraying concrete again to form multilayer extension support; constructing a reinforced concrete lining structure on the inner side of the multilayer extension support, and forming the multistage pressure-yielding and pressure-resisting support structure through the long anchor cables, the short anchor rods, multilayer support and the reinforced concrete lining structure. According to the extremely-high geostress soft rock large-deformation tunnel multistage pressure-yielding and pressure-resisting support structure, the pressure is actively released by reserved deformation; the long anchor cables and the short anchor rods are used for anchoring in time with high pre-tightening force, enabling the pressure of the surface surrounding rock to be transferred to the deep part of the surrounding rock and expanding the surrounding rock bearing ring; the pressure-yielding support structure is used for providing high resistance and continuous deformation capacity; the reinforced concrete structure is used for resisting rheomorphism; the deformation of the surrounding rock can be effectively controlled; long-term stability of the structure can be ensured.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a multi-level yielding support structure and a construction method for a tunnel with extremely high ground stress and large deformation in soft rock. Background technique [0002] With the improvement of road grades, the number of long, large and deep tunnels is increasing, and the geological conditions encountered are more complex and the ground stress is higher. During the construction process, there will be more geological disasters, such as hard rock rockburst, soft Large deformation of rock, karst water inrush and other problems. Due to the unclear understanding of the mechanism of geological disasters, design and construction according to conventional concepts will lead to the incompatibility of the supporting structure and construction method with the geological environment, resulting in the occurrence of various catastrophic accidents, especially soft rock lar...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a multi-stage yielding support structure and construction method of a soft rock large deformation tunnel with extremely high ground stress. Long-term impact, fully tap the self-supporting capacity of the surrounding rock, and use active anchorage, stress release, yielding support, and high-strength lining structures as means to combine shallow support and deep anchorage to expand the bearing circle, so that the resistant support structure can be supported synergistically. It can effectively control the deformation amount and deformation rate of surrounding rock, avoid frequent dismantling and replacement of arches due to the encroachment of support structures, slow construction progress, and sharp increase in engineering costs, greatly improving construction safety and reliability of support structures

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