Active and pile-slab combined tunnel supporting system for karst cave group crossing and construction method

Abstract

The invention discloses an active and pile-slab combined tunnel supporting system for karst cave group crossing and a construction method. The active and pile-slab combined tunnel supporting system ischaracterized in that a steel arch above arc feet in an initial supporting system is positioned in an arch karst cave; the front end of an anchor cable is anchored in an arch firm sock; the tail of the anchor cable is fixedly welded onto the steel arch; an active support to a tunnel is achieved through the anchor cable; foot-lock anchor pipes and a transverse temporary inverted arch are arrangedat the positions of the arch feet so as to form the initial supporting structure; aimed at a bottom covered karst cave, a plurality of pipe foundations are arranged so as to form a pile foundation group in an area where the bottom covered karst cave is positioned; a raft slab is supported by the pile foundation group so as to form a bearing system; the raft slab and the inverted arch are set to bean integrated pouring structure; and reinforcing bars in the raft slab and the steel arch in the initial supporting system are fixedly welded. Through the active support and a pile slab, a combined supporting and bearing system is formed, so that the safety of tunnel excavation in a large-sized karst cave group and the bottom structure safety can be achieved.

Description

technical field [0001] The invention relates to the field of traffic tunnel construction, and more specifically relates to an active support and pile-slab combination system and construction method for tunnels passing through karst cave groups, especially for tunnel construction in karst cave development areas. Background technique [0002] In some areas, there is a large area of ​​limestone distribution. For example, the exposed area of ​​Guangxi, China is 120,000 square kilometers, accounting for about 60% of the total area of ​​Guangxi; There are sharp and steep limestone peaks with different shapes, such as sharp cones, swords, columns, and towers. There are many hidden karst caves in this area, and the possibility of encountering karst caves during tunnel excavation is extremely high. Before construction, karst caves should be detected from the surface. The difficulty is huge and the construction risk is extremely high. Especially in the complex large-scale karst cave ...

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Problems solved by technology

[0002] In some areas, there is a large area of ​​limestone distribution. For example, the exposed area of ​​Guangxi, China is 120,000 square kilometers, accounting for about 60% of the total area of ​​Guangxi; There are sharp and steep limestone peaks with different shapes, such as sharp cones, swords, columns, and towers. There are many hidden karst caves in this area, and the possibility of encountering karst caves during tunnel excavation is extremely high. Before construction, karst caves should be detected from the surface. The difficulty is huge and the construction risk is extremely high

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