Peripheral hole arc-shaped drilling construction method for controlling tunnel overexcavation

Abstract

The invention discloses a peripheral hole arc-shaped drilling construction method for controlling tunnel overexcavation, and relates to the technical field of tunnel construction. The method comprises the following steps that S1, a drill rod is used for drilling towards the front of a tunnel in the direction forming an outer included angle 22 with the axis of the tunnel at the position close to the excavation contour line of the tunnel face, and the drilling length is L0; and S2, external force F1 facing the inner side of the tunnel and external force F2 facing the outer side of the tunnel are continuously applied to the tail end of the drill rod and the position close to a hole opening, so that the drill rod generates deformation protruding towards the inner wall of the tunnel and continuously drills holes, and the straight holes can be changed into arc-shaped holes through drilling in the state. According to the construction method, the arc-shaped tunnel drilling and blasting peripheral holes can be drilled, and compared with linear peripheral holes with the same footage length, the tunnel overexcavation amount can be effectively reduced.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to an arc-shaped drilling method for peripheral holes for controlling tunnel overexcavation. Background technique [0002] As an indispensable and main tunnel rock breaking method, the drill and blast method is a method of excavating rock by drilling, charging, and blasting. In the drilling and blasting construction, manual hand-held pneumatic drills or construction machinery including but not limited to rock drilling rigs must be used to drill holes in the rocks and then fill them with explosives. When drilling holes around the tunnel, due to the limitations of the drilling machine structure As a result, there must be an extrapolation angle in the borehole, and there will be a certain amount of overbreak phenomenon, especially the overbreak phenomenon of mechanical drilling is particularly serious. The overbreak part must be backfilled with concrete to control the tunne...

AI Technical Summary

Problems solved by technology

In the drilling and blasting construction, manual hand-held pneumatic drills or construction machinery including but not limited to rock drilling rigs must be used to drill holes in the rocks and then fill them with explosives. When drilling holes around the tunnel, due to the limitations of the drilling machine structure As a result, there must be an extrapolation angle in the borehole, and there will be a certain amount of overbreak phenomenon, especially the overbreak phenomenon of mechanical drilling is particularly serious. The overbreak part must be backfilled with concrete to control the tunnel size. The concrete backfill caused by overbreak is not only It will increase the project cost, and in some weak and broken surrounding rocks, it will also affect the safety and quality of tunnel construction and delay the construction period. Therefore, how to control overexcavation more effectively is an important problem to be solved in tunnel drilling and blasting construction.

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