Pilot tunnel type internal blasting method for rockburst stress relief in long diversion deep-buried circular tunnel

Abstract

The invention provides an internal blasting method of demolishing a pilot hole based on rock-blasting stress produced by long diversion water deep buried in a circular tunnel, which can reduce or eliminate the degree of energy accumulation and solve the problems of construction safety and construction schedule caused by strong rock burst. The internal blasting method of demolishing the pilot holebased on the rock-blasting stress produced by the long diversion water deep buried in the circular tunnel is implemented according to the following methods: (1) a pilot hole is excavated first; (2) after the pilot hole is excavated, concrete is used for carrying out the surrounding rock spraying for the pilot hole; after 12-16 hours, three blasting hole groups are arranged along the direction vertical to the pilot hole, and eight holes are evenly arranged at each blasting hole group; (3) during initiation, the three holes are initiated in the following order: the top hole and the middle-upperhole are blasted first, then the middle hole, and finally the bottom hole and the middle-lower hole are blasted; after the blasting is completed, the slag is discharged; (4) after the slag discharge is completed, the pilot hole - drilling - blasting - slag discharge is carried out according to the above steps until the whole stress concentration zone is completely passed. The internal blasting method of demolishing the pilot hole based on the rock-blasting stress produced by the long diversion water deep buried in the circular tunnel can control rock burst by changing the properties of surrounding rock mass, reducing or eliminating the degree of energy accumulation, and by reducing or eliminating the blasting energy.

Description

technical field [0001] The invention relates to water conservancy projects, in particular to a circular tunnel rockburst stress relief blasting method. Background technique [0002] Rockburst is the destruction of surrounding rock caused by the sudden release of potential energy or strain energy accumulated in the rock mass during the excavation process of underground engineering, which can lead to casualties, damage to the working face or equipment, and its basic characteristics are sudden and violent. Especially if a large circular excavation surface (such as a water diversion tunnel or a flood discharge tunnel) is encountered, affected by its stress distribution characteristics, not only the top and side walls are prone to rockburst, but even the bottom of the cavern will crack. Causing deformation and collapse of the cavern, and even destroying the entire project. When this kind of rockburst occurs, the vibration is strong, the duration is long, and the damage range is ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a long water diversion deep buried circular tunnel rockburst stress relief pilot tunnel type internal blasting method, which can reduce or eliminate the degree of energy accumulation and solve the construction safety and construction progress problems caused by strong rockbursts

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