Narrow rock wall crane beam excavation method

Abstract

The invention discloses a narrow rock wall crane beam excavation method. The method comprises the steps that after excavation of a cavern top layer is completed, excavation of a cavern rock wall cranebeam layer is conducted in a partitioned mode from the middle to the two sides; firstly, a middle groove area is excavated, protective layers on the two sides are stripped at a time, and after supporting is completed, pre-splitting blasting excavation is conducted on inclined face holes of a rock table, and blasting holes are drilled and blasted from a side wall of a cavern along a designed inclined face of the rock table and perpendicular to the trend axis of the cavern for drilling hole blasting; and then horizontal smooth blasting of a straight side wall on the rock table is conducted, andthe blasting holes are horizontally drilled and blasted in the direction parallel to the excavation direction of the cavern for horizontal drilling hole blasting. According to the narrow rock wall crane beam excavation method, pre-splitting blasting is carried out on the inclined surface in advance, inclined surface cracks and turning points of a rock wall crane beam are formed in advance, the situation that horizontal smooth blasting must be adopted to tear and damage a rock mass when side wall vertical smooth blasting cannot be implemented can be avoided, rock table forming quality is improved, and meanwhile rock table rock mass quality is improved; and in addition, vertical holes and inclined holes do not need to be aligned one by one, and only the depth needs to be strictly controlled, so that the workload of surveying, setting-out and checking is reduced.

Description

technical field [0001] The invention relates to the excavation technology of the rock wall crane beam engineering of water conservancy and hydropower underground powerhouses or sluice chambers, and belongs to the underground engineering construction technology, in particular to a rock wall beam excavation construction method with insufficient drilling and blasting operation space at the top of the rock wall crane beam . Background technique [0002] Generally, the excavation method of the crane beam on the rock wall of the underground powerhouse adopts the construction technology of pulling the groove in the middle + reserved protective layer + rock platform excavation. Among them, the rock platform is the key to the excavation quality. The simultaneous blasting method of the vertical hole and the inclined hole of the platform is currently widely used in the excavation of rock wall crane beams for underground powerhouses of water conservancy and hydropower projects. This me...

AI Technical Summary

Problems solved by technology

Due to the limited space at the top, it is impossible to construct the vertical hole of the rock platform. The inflection point of the rock platform is greatly damaged by directly adopting the horizontal smooth surface blasting method, and it is difficult to control over- and under-excavation, and it is difficult to form the rock platform.

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