Large-deformation preliminary bracing system for high-ground-stress soft rock

Abstract

The invention relates to a large-deformation preliminary bracing system for a high-ground-stress soft rock. The large-deformation preliminary bracing system comprises multiple circles of H-shape-steelsteel arch centers, wherein the multiple circles of H-shape-steel steel arch centers are longitudinally arranged in parallel; two longitudinal steel arch centers are connected by adopting a longitudinal connecting steel bar or channel steel; a single steel arch center is circumferentially divided into multiple segments; nodal points are connected through socket and spigot steel arch center joints; a longitudinal groove is reserved in a preliminary bracing sprayed concrete layer between the nodal points of two adjacent steel arch centers; compressible steel tubes are arranged in the longitudinal grooves. According to the large-deformation preliminary bracing system, by utilizing the compressible steel tubes which are longitudinally embedded into precast sprayed concrete and can provide resistance and spigot and socket section-steel steel frame joints corresponding to the compressible steel tube, the concession is carried out while the resisting is carried out; the deformation is enabled to be controllable; the deformation pressure borne of a preliminary bracing is released and the structural stableness of the preliminary bracing is realized.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a large-deformation primary support system for soft rock with high ground stress. Background technique [0002] At present, more and more tunnel projects pass through large-scale soft rock formations with high geostress, and the problem of large deformation disasters is prominent during tunnel construction, which seriously endangers the safety of tunnel construction and operation. The self-supporting capacity of the surrounding rock of the soft rock tunnel with high ground stress is poor, and the deformation speed is fast after excavation, which is difficult to control, and often causes instability and collapse. After a period of time in the secondary lining, bottom heaving, side wall sinking, and lining cracking occurred, which not only increased the construction workload, but also caused great losses. [0003] Therefore, the construction of the above working condit...

AI Technical Summary

Problems solved by technology

However, the rigidity of this kind of shrinkable steel arch is relatively small, and the joints are easily damaged. When there is no longitudinal joint of shotcrete, the shotcrete at the joint is easily crushed and cracked, which reduces the overall bearing capacity of the shotcrete; when longitudinal joints are provided, due to If it is not closed, the surrounding rock is easy to extrude from the longitudinal joints, and even a debris flow is formed, resulting in the formation of a cavity behind the support to induce landslides and structural instability

[0005] In summary, the current support methods for general soft rock tunnels may not be suitable for large deformation soft rock tunnels under complex geological conditions, and cannot effectively control the large deformation of tunnels

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