Upper step base plate minimally invasive blasting structure and minimally invasive blasting excavation method for maintaining tunnel step stability

A bench and floor technology, applied in the field of minimally invasive blasting excavation, can solve the problems of short bench length, affecting the stability of the face, and achieve the effect of improving the degree of damage and the looseness of the rock.
CN110608642AActive Publication Date: 2019-12-24中铁二局第二工程有限公司
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
中铁二局第二工程有限公司
Publication Date
2019-12-24

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Abstract

The invention relates to the technical field of related tunnel construction, in particular to an upper step base plate minimally invasive blasting structure. A base plate hole is formed in a base plate area of an upper step; the base plate hole comprises bottom angle holes positioned at two horizontal ends, and a middle hole set positioned between the two bottom angle holes; the bottom angle holesadopt detonating cord explosive string structures; a horizontal adjacent hole adopts an air interval explosive loading structure; a vertical adjacent hole is designed according to a conventional light blasting hole; the middle holes beyond the horizontal adjacent hole adopt continuous explosive loading structures; the base plate hole blasting sequence is from middle in sequence; one section of afirst blasthole on an adjacent upper row is behind; through design of hole net parameters of the base plate hole, the explosive unit consumption, the explosive loading structures and the blasting network, the lower step free surface damage degree of the base plate hole is improved; and the rock looseness is better after blasting of the base plate hole, so that the base plate blasting minimally invasive molding in a micro step method is realized.
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Description

technical field

[0001] The invention relates to the technical field related to tunnel construction, in particular, to a minimally invasive blasting structure for an upper-step bottom plate and a minimally invasive blasting excavation method for maintaining the stability of tunnel steps. Background technique

[0002] The most commonly used construction method of tunnel drilling and blasting is the upper and lower step method (applicable to III, IV and V surrounding rocks), which is further refined into micro-step method according to the different step lengths (the upper step length is 3-5m, suitable for III, IV , Grade V surrounding rock), short-step method (the length of the upper step is 10-15m or B-1.5B, B is the tunnel excavation width, applicable to Grades III, IV, and V surrounding rock) and long-step method (the length of the upper step ≥ 5B, generally used in level III, is not commonly used now). Theoretically speaking, compared with the short-step method and long-st...

Claims

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