Smooth blasting method applied to soft rock and extremely soft rock

Abstract

A smooth blasting method applied to soft rock and extremely soft rock includes the steps of performing holing and explosive loading on a working plane and performing detonation. The step of holing concretely includes the steps that drilling is performed along the boundary contour line of the periphery of the working plane, a smooth blasting layer is composed of rock masses between a periphery smooth blasting hole array located on the boundary contour line and an outer ring falling hole array close to periphery smooth blasting holes, and a treatment insufficient excavation short hole array is further arranged on the outer side of the periphery smooth blasting hole array; outer ring falling holes and the periphery smooth blasting holes are designed according to smooth blasting of the soft rock to form double-layer smooth blasting. Explosives and detonating cords are loaded into treatment insufficient excavation short holes and the outer ring falling holes, and explosive loading of the periphery smooth blasting holes includes the two modes that only the detonating cords are loaded or the detonating cords are loaded, and the explosives are loaded into the bottom of a small quantity of holes. By the adoption of the smooth blasting method applied to the soft rock and the extremely soft rock, disturbance on surrounding rock by detonation is effectively reduced, it is avoided that due to detonation vibration and impact, a large amount of surrounding rock is excessively excavated, and the detonation falling effect of the rock layer is quite good.

Description

technical field [0001] The invention belongs to the technical field of engineering blasting, and relates to a smooth blasting technology, in particular to a smooth blasting method applied to soft rock and extremely soft rock. Background technique [0002] At present, smooth blasting is mainly used in tunnel excavation to control the excavation profile. In general smooth surface blasting, the charge density of a single hole line in soft rock is 70-120g / m3, but for soft rock and extremely soft rock, even though the adjacent caving holes create a free surface for it, the thickness of the light blast layer may still occur. Inhomogeneity affects the light blasting effect, or the rock is too soft, and the amount of chemical in the hole is too large, resulting in poor light blasting effect. In 1999, when the soft surrounding rock at the entrance of Xu'ao Tunnel of Zhaoshandu Water Diversion Project in Wenzhou was excavated, it was successfully used. Peripheral dense hole drilling ...

AI Technical Summary

Problems solved by technology

[0007] In order to overcome the technical defects of large-section blasting in soft rock or extremely soft rock in the prior art that the drilling workload is large in the early stage and the rock mass is not easy to fall off after blasting, the invention discloses a smooth surface blasting applied to soft rock and extremely soft rock method

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