Underground cavern top arch shallow surface layer surrounding rock low-pressure grouting method

Abstract

The invention relates to a low-pressure grouting method for shallow surface layer surrounding rock of an underground cavern top arch. According to the technical scheme, the low-pressure grouting method for the shallow surface layer surrounding rock of the top arch of the underground cavern is characterized in that supporting measures of corresponding parts of the top arch of the underground cavern are completed before low-pressure grouting; grouting hole site lofting and trepanning at the corresponding part of the top arch of the underground cavern are completed; all the grouting holes are divided into I-sequence grouting holes for first grouting and II-sequence grouting holes for later grouting, sequential grouting is carried out according to the principle of gradual densification, a full-hole one-time grouting method is adopted, and stop-grouting plugs are arranged at openings of the grouting holes; grouting materials of the I-sequence grouting holes are ordinary Portland cement, the water-cement ratio of the ordinary Portland cement has multiple levels, and when the injection rate is larger than a preset value, grout with the water-cement ratio concentrated by one level is adopted for grouting; superfine cement is adopted as a grouting material of the II-sequence grouting holes, the water-cement ratio of the superfine cement has multiple levels, and when the injection rate is larger than a preset value, grout with the water-cement ratio being one level thick is adopted for grouting.

Description

technical field [0001] The invention relates to a low-pressure grouting method for the surrounding rock of the shallow surface layer of the top arch of an underground cavern. It is suitable for the shallow surrounding rock of the top arch of the underground cavern under the action of high in-situ stress or unfavorable geological structure. Background technique [0002] The top arch of the underground cavern can maintain the stability of the top arch by relying on the integrity and bearing capacity of the surrounding rock during and after the excavation. However, under the action of high ground stress or unfavorable geological structure, the surrounding rock stress of the top arch will continue. The adjustment will lead to the relaxation and rupture of the superficial surrounding rock, weaken the integrity and bearing capacity of the surrounding rock, and even cause the relaxation circle of the surrounding rock to further expand to the deep, threatening the overall safety of ...

AI Technical Summary

Problems solved by technology

[0002] During the excavation period and after the completion of the excavation, the top arch of the underground cavern can maintain the stability of the top arch by relying on the integrity and bearing capacity of the surrounding rock itself. The adjustment leads to loosening and cracking of the shallow surrounding rock, weakening the integrity and bearing capacity of the surrounding rock, and even causing the relaxation circle of the surrounding rock to further expand to the deep, threatening the overall safety of the underground cavern

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