A construction method for reducing blasthole control over and under-excavation in an inclined flat-curve tunnel

Abstract

The invention discloses a construction method for reducing blasting and under-excavation in an inclined flat-curve tunnel. The method includes: designing a construction method, optimizing a tunnel excavation contour; , Peripheral long eye and peripheral short eye, the undercut eye is symmetrically spaced on both sides of the tunnel centerline, the undercut eye is arranged on the outside of the undercut eye, and the undercut eye and the undercut eye are arranged at intervals; the peripheral long eye and the peripheral The short eyes are evenly spaced along the tunnel excavation outline and located inside the tunnel excavation outline, and the peripheral short eye is arranged on the tunnel face between the peripheral long eye and the reaming eye. The beneficial effects of the present invention are as follows: the blasthole construction method of the present invention comprehensively considers the influence of factors such as the tunnel inclination angle and the side wall of the flat-curve tunnel, and proposes a peripheral hole arrangement form pertinently, which is consistent with the existing universality. Compared with the method of blasting holes in the tunnel, the amount of over- and under-excavation is reduced.

Description

technical field [0001] The invention belongs to the field of tunnel engineering, and in particular relates to a construction method for reducing blastholes with controlled blasting and underexcavation in inclined flat curve tunnels. Background technique [0002] In recent years, with the continuous increase of the construction volume of tunnel projects in my country, the effective control of tunnel over-under-excavation and vibration velocity has become the focus of all parties involved in the construction. (Structures) There are many kinds of influencing factors, tunnel over-under-excavation and vibration speed control have brought severe challenges. The existing research results of tunnel over-under-excavation control technology are mainly aimed at small-slope tunnels or near-horizontal tunnels. The arch adopts the form of long and short blastholes or dense holes and spaced holes. Technical measures such as Φ108mm tube shed and Φ42mm small conduits reduce the vibration spe...

AI Technical Summary

Problems solved by technology

If the influence of the steel frame on the drilling of the arch is only considered, and the factors affecting the tunnel slope and flat curve are ignored, then under the same hole layout conditions that still consider the extrapolation angle, the degree of overbreak and underbreak of the tunnel arch and side walls will be extremely large. There may be a risk of further increase, and the actual amount of concrete spraying will further increase

At present, how to reasonably and effectively reduce the degree of over- and under-excavation of curved side walls is still somewhat rare.

[0004] (2) Vibration reduction control measures such as pipe shed and small pipe grouting in a certain area of ​​the arch will reduce the construction progress and increase the cost of construction measures to a certain extent; on the other hand, increasing construction investment will often be accepted by the construction party Low, more difficult to implement

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