Reinforcement method of interlayer rock in small clear distance tunnel under different surrounding rock grades

Abstract

The invention provides a method for reinforcing interlaid rocks of a small-distance tunnel under different surrounding rock grades. The method comprises the following steps: step one, looking up a tunnel design and construction scheme to determine thicknesses and heights of the interlaid rocks, distances among steel arches, models of joist steels of the steel arches and widths of wings, and looking up a geological survey report to determine geological surrounding rock grades and surrounding rock porosity in a construction site; step two, enhancing pre-grouting for construction of a previous tunnel; step three, reinforcing longitudinal steel beams for construction of the previous tunnel; step four, enhancing pre-grouting for construction of a following tunnel; and step five, reinforcing longitudinal steel beams for construction of the following tunnel. Pre-grouting reinforcement on the interlaid rocks with different surrounding rock grades is carried out before tunnel excavation, advance supporting and interlaid rock stability reinforcing are combined, and construction steps are simplified; the longitudinal steel beams are used to reinforce the interlaid rocks, and therefore, a supporting structure is strengthened. By the method, stability of the interlaid rocks can be guaranteed, furthermore, a construction technology can be simplified effectively, and construction progress is accelerated.

Description

technical field [0001] The invention relates to a construction method in the technical field of tunnel engineering, in particular to a method for reinforcing interlayer rocks in tunnels with small clear distances under different surrounding rock grades. Background technique [0002] In the construction of small-space tunnels, interlayer rock is the rock mass located in the middle of the double-arch structure of small-space tunnels, which plays an important role in maintaining the stability of the tunnel and supporting the upper structure of the tunnel. During the construction of the tunnel with a small clear distance, stress concentration and secondary stress field superposition occur at the interlayer rock, which is prone to instability. When the surrounding rock conditions are grade I and II, the interlayer rock can maintain better stability, when the surrounding rock conditions are III, IV, and V, the interlayer rocks are prone to cracking and falling blocks, and collapse...

AI Technical Summary

Problems solved by technology

"Although this patent simplifies the construction steps of applying prestressed reinforcement to the horizontal through-bolt, it has carried out repeated reinforcement of the interlayer rock with advanced pipe shed and small grouting pipe grouting, and the process is complicated; the layout of small grouting pipes 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

Images