Segmented blasting hole excavation construction method for reconstruction and expansion of tunnel through karst landform water conservancy extra-small section

Abstract

The invention discloses a segmented blasting hole excavation construction method for reconstruction and expansion of a tunnel through a karst landform water conservancy extra-small section. The segmented blasting hole excavation construction method is used for reconstruction and expansion of an original tunnel. The original tunnel is the extra-small section, and the excavation section is designedto be in a city door hole type. The segmented blasting hole excavation construction method comprises the following steps that S1, on-site reconnaissance and investigation are conducted on surroundingrock of the original tunnel, the existing state of the surrounding rock is actually mastered, and the category classification of the surrounding rock is confirmed to be IV or V; S2, advanced reinforcement is conducted on the existing state of the existing surrounding rock found through investigation in the step S1; and S3, classified blasting and segmented blasting of the same tunnel face are conducted on excavated different surrounding rock tunnel faces. A segmented blasting method in the step S3 comprises the steps that firstly, the top part of the original tunnel is excavated through blasting, and then a side wall and an inverted arch are excavated through blasting; or the position of the side wall is blasted firstly, and then the position of an arch crown is detonated. The segmented blasting hole excavation construction method has the characteristics of being safe, reliable, easy to construct and operate, remarkable in economic benefit and the like, can be widely applied to the field of water conservancy, mine and underground engineering widening construction, and is wide in application and popularization prospect.

Description

technical field [0001] The invention relates to a tunnel construction method, in particular to a subsection blasting hole excavation construction method for rebuilding and expanding tunnels with special small sections in karst landforms. Background technique [0002] When the karst landform tunnel was expanded, the surrounding rocks of the original tunnel were mainly of type V~IV through field investigation. Since the site area is located in the karst landform belt, the vertical fractures of many rock masses in the surrounding rocks are relatively developed, and the karst is relatively developed. broken body. The development of fissures, coupled with the poor control of the blasting charge in the original tunnel, aggravated the further fragmentation of the surrounding rock. The position of the axis of the original tunnel body is very random, with almost no straight line. It basically belongs to the situation where the axis of the tunnel is where the original excavation and ...

AI Technical Summary

Problems solved by technology

Seriously affect the safety of tunnel construction and later use functions. In addition, the geological conditions are complex, and the

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