Columnar joint surrounding rock anti-relaxation supporting method for underground cavern

Abstract

The invention discloses a columnar joint surrounding rock anti-relaxation supporting method for underground cavern excavation. The columnar joint surrounding rock anti-relaxation supporting method caneffectively control the relaxation deformation and damage phenomena of columnar joint rock mass due to excavation unloading, and has important significance for engineering safety and economy. The method comprises the following steps that geological survey is conducted on the columnar joint rock mass in an excavation area, an indoor mechanical test is carried out, and rock mass mechanical parameters are obtained and calibrated; a cavern excavation calculation model is established, surrounding rock excavation unloading numerical simulation is carried out, the relaxation depth and relaxation range are determined, and the aging characteristic and anisotropic characteristic of relaxation deformation are analyzed; cavern excavation is conducted in a layered mode, the excavation face is sealed through shotcrete after excavation of all layers is completed, and prestressed anchor rods are arranged according to the surrounding rock relaxation range for primary tensioning; according to the columnar joint rock mass excavation unloading aging characteristic, the area with the large relaxation depth is reinforced through prestressed anchor cables and subjected to primary tensioning; and grouting holes are drilled, and consolidation grouting is conducted on surrounding rock.

Description

technical field [0001] The invention relates to an anti-relaxation support method for columnar joint surrounding rock, which is suitable for the excavation support design of columnar joint rock mass in underground caverns. Background technique [0002] Columnar joints are a kind of primary tensional fracture structure commonly found in basalts, which are widely distributed in Southwest China. With the development of my country's infrastructure, more and more projects involve columnar jointed rock mass. [0003] Columnar jointed basalt is a typical jointed rock mass. The rock is firm and the joints are tightly occluded. The quality is good before excavation. collapse etc. According to the test results on the project site, it is found that the surrounding rock of columnar jointed basalt caverns shows obvious relaxation and deformation characteristics. The greater the degree of relaxation of the surface, the worse the quality of the rock mass. The relaxation degree of the s...

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Problems solved by technology

[0005] The present invention aims at the problem that the above-mentioned columnar joint rock mass unloads and is easy to relax, which affects the stability of the underground cavern and increases the investment in the later stage of the project. It provides a columnar joint surrounding rock support method for underground cavern excavation, which can effectively Controlling the relaxation, deformation and failure of columnar jointed rock mass due to excavation and unloading is of great significance to engineering safety and economy

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