Protection structure of karst cave at upper part of tunnel

Abstract

The invention discloses a protection structure of a karst cave at the upper part of a tunnel. The protection structure comprises a concrete protection arch, an outer layer protection arch, a concretebuffer layer, a sand buffer layer and a concrete guard wall. The concrete protection arch is tightly adjacent to a tunnel initial support, and the outer contour of the concrete protection arch is thesame as that of the tunnel initial support; the outer layer protection arch is tightly adjacent to the concrete protection arch, and has the same outer contour as the concrete protection arch; the concrete buffer layer is tightly adjacent to the outer layer protection arch, and fills a cavity defined by the outer layer protection arch and the inner wall of the karst cave; the sand buffer layer istightly adjacent to the concrete buffer layer and fills a cavity defined by the top of the concrete buffer layer and the inner wall of the karst cave in the preset height; and the concrete guard wallextends from the bottom of the karst cave to the earth surface on the top of the karst cave along the side wall of the karst cave, and surrounds a tunnel. The protection structure is high in construction efficiency and low in risk in the construction process, can reasonably treat the cavity karst cave at the upper part of the tunnel and enables the structure to be safe and stable, improves the construction quality of the tunnel project, accelerates the construction progress, and ensures the safety in the construction period and the stability in the operation period.

Description

Technical field [0001] This application relates to the field of road and bridge construction, and in particular to a method for treating the cavern in the upper part of the tunnel. Background technique [0002] Karst areas have complex geological structures, often with fractures, faults, karst caves and the characteristics of mud and water. In the process of tunnel excavation, if there is a cavernous geological body in the upper part, there will be the danger of falling blocks and collapsing, mud and water inrush. The collapse of karst caves is caused by the destruction of the integrity and stability of the soluble rock in the formation under the action of dissolution, and the strength of the surrounding rock decreases. Under construction disturbance, part of the rock mass may break away from the parent rock or even collapse as a whole. It is determined by the degree of hydraulic connection between the cave and the surrounding medium and the surface, not a random phenomenon. On...

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Problems solved by technology

[0003] The traditional reinforcement and backfill treatment methods for the upper cavity of the tunnel are generally used to resist the impact load caused by the collapse of the top of the cave and avoid damage to the initial support. Blocking, diversion and other measures, if subsequent mud inrush and karst continue to develop, these existing technologies will have great safety hazards when dealing with large mud inrush caves in the upper part of the tunnel, and cannot guarantee construction safety and tunnel structure stability

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