Smooth blasting method for tunnel weak surrounding rock

Abstract

The invention discloses a smooth blasting method for tunnel weak surrounding rock. The blasting method comprises the steps that a large-diameter auxiliary slotting hole is formed, the bottom of the hole is filled with a cartridge, a water bag is arranged on the upper portion of the cartridge, and a hole opening is blocked by a water sandbag; or the blasting method adopts an energy-gathered water pressure peripheral hole blasting mode, blasting shock waves are released and transmitted to the rock wall through kerfs of an energy-gathered pipe to form cracks, which are communicated with one another, and finally a complete surrounding rock loose circle is formed. Energy loss caused by plastic deformation in ore rock can be reduced or eliminated, so that the utilization rate of explosives can be greatly improved, and the utilization rate of shot holes is greatly improved. The damage of blasting to the rock is further enhanced, the blasting area is increased, and the blasting footage is increased.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a smooth surface blasting method for weak surrounding rock of a tunnel based on water bag interval cut holes and energy-gathering water pressure surrounding holes. Background technique [0002] The tunnel passes through unfavorable geological areas. Due to the ups and downs of the terrain, the serious water gushing in folded faults and surrounding rock fissures, the weak surrounding rock, the large proportion of broken strata, and the possibility of karst, etc., have brought great difficulties to the tunnel construction. Weak and broken surrounding rock is the most common unfavorable geology in tunnel construction, and it is also an important factor affecting the stability of tunnel surrounding rock. Usually, weak and broken surrounding rock is in a stable state. When affected by external forces such as blasting and excavation, the weak and broken surrounding rock The...

AI Technical Summary

Problems solved by technology

Over- and under-excavation of the tunnel will first affect the construction progress, resulting in a relatively long time for slag discharge in the tunnel, and a long period for construction personnel to construct the support structure; at the same time, over- and under-excavation will affect the quality of the project, resulting in insufficient support thickness. When the thickness reaches a certain value When overcutting, it will have an adverse effect on the quality acceptance of the project, and the recessed part of the overcut will also affect the adhesion of the concrete; in addition, overcutting and undercutting will increase the project cost, increase the material cost and personnel cost of the project, and lead to an increase in the project cost; finally , over-excavation and under-excavation will affect the stability of the surrounding rock of the tunnel. For the over-excavation part, secondary blasting will be carried out, which will cause unfavorable disturbance to the surrounding rock.

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