SUPPORT SYSTEM FOR TUNNEL IN LARGE KARST CAVE

摘要

A support system for a large karst cave tunnel comprising a column support structure and a frame tunnel structure, wherein the column support structure being arranged on two sides of the tunnel in the karst cave for supporting the top (2) of a karst cave (1); the frame tunnel structure consisting of a lower tunnel frame (7) and an upper support frame, the upper support frame being arranged above the lower tunnel frame and joined as one unit; the inside contour of the tunnel cavity of the lower tunnel frame is identical to a normal tunnel; the upper support frame extending to the top (2) of the karst cave (1). A cavity with an open upper part is arranged on the top of the upper support frame, the open part of the cavity corresponding to the top of the karst cave, and the cavity is backfilled with concrete (8) and closely contacting the top of the karst cave. The large karst cave tunnel support system employs the column support structure and the frame tunnel structure for the active protection of the top of the karst cave, prevents damages to the tunnel structure when the unstable rock mass of the karst cave top plate falls, fully utilizes the protection capability of the structure, reduces the project cost, and ensures the safety and reliability of the tunnel structure.