Stability control method for mountainous area weak surrounding rock small-distance tunnel mid-adjacent rock

Abstract

The invention provides a stability control method for mountainous area weak surrounding rock small-distance tunnel mid-adjacent rock. The method includes the steps that firstly, a geological survey report is looked up to determine the level of geological surrounding rock of a construction site, a tunnel design and construction scheme is looked up to determine the thickness of the mid-adjacent rock and the span of a single hole of a tunnel, and whether engineering conditions required by the method are met or not is judged; secondly, the tunnel design and construction scheme is looked up to determine the height of the mid-adjacent rock, the steel arch distance and the type and flange width of I steel adopted by steel arches, and the geological survey report is looked up to determine the surrounding rock porosity; thirdly, machining parameters of small grouting ducts and advanced grouting pipes are determined; fourthly, machining parameters of longitudinal steel beams are determined; fifthly, advanced grouting reinforcement is constructed; and sixthly, longitudinal steel beam reinforcement is constructed. By means of the stability control method, the deformation and the load acting on a support structure of the small-distance tunnel mid-adjacent rock are effectively reduced, the stability of the steel arches is improved, shearing stress caused by asymmetrical construction of advanced tunnels and subsequent tunnels is reduced, the support structure is reinforced, and the construction process is simplified.

Description

technical field [0001] The invention relates to a construction method in the technical field of tunnel engineering, in particular to a method for controlling the stability of interbedded rock in tunnels with weak surrounding rocks and small clear distances in mountainous areas. Background technique [0002] In the construction of small clear distance tunnels, weak surrounding rocks refer to surrounding rocks with weak rock quality, low bearing capacity, developed joints and fissures, and broken structures. Commonly, they are grade IV, V and VI surrounding rocks. The rock mass in the middle of the double arch structure of the tunnel plays an important role in maintaining the stability of the tunnel and supporting the upper structure of the tunnel. During the construction of small clear distance tunnels under weak surrounding rock conditions, stress concentration and secondary stress field superimposition occur in the interlayer rock, which is prone to cracking and block loss,...

AI Technical Summary

Problems solved by technology

"Although this patent simplifies the construction steps of applying prestressed reinforcement to the horizontal through-bolts, the interlayer rocks are repeatedly reinforced with advanced pipe shed and advanced grouting pipe grouting, and the process is complicated; the scope of advanced grouting pipe layout ranges from tunnel The spandrel on the side away from the interlayer rock extends to the arch foot on the side close to the interlayer rock. The layout range is large and the construction period is long; no interlayer rock reinforcement measures are proposed for different surrounding rock conditions

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