Three-step five-part excavating constructing method for small-section weak surrounding rock tunnel

Abstract

The invention discloses a three-step five-part excavating constructing method for a small-section weak surrounding rock tunnel. The three-step five-part excavating constructing method for the small-section weak surrounding rock tunnel comprises the following steps that 1, an upper step is formed through one-time drilling-blasting excavating, and it is ensured that left and right step staggered joints of a middle step and a lower step is more than 5m according to the surrounding rock situation; 2, slag turning is conducted on the upper step, and deslagging is conducted on the middle step and the lower step; 3, I steel is erected on the upper step and the middle step for net hanging and guniting, and deslagging is conducted on the lower step; 4, an advanced pipe shed is constructed for the upper step, slag turning is conducted on the middle step, and I steel is erected on the lower step for net hanging and guniting; and 5, continuous deslagging is conducted through a tunnel main cave and a deviated well. By means of the three-step five-part excavating constructing method for the small-section weak surrounding rock tunnel, according to the disadvantageous geological condition that weak surrounding rock and faults of steep-slope long-deviated-well water conservancy tunnels are rich in water and the characteristic that the deslagging process is used as the key controlling process of the construction schedule during the tunnel excavating process, the excavated operation side is disassembled, the operation space is enlarged, the parallel operation range of operation time is refined, continuous deslagging is achieved, the difficulties that deslagging time and the process circulating period are long are overcome, and the construction schedule is accelerated on the premise of ensuring the construction quality and safety.

Description

technical field [0001] The invention relates to a three-step five-part excavation construction method for a small-section weak surrounding rock tunnel. Background technique [0002] Weakness and faults in the construction of small and medium-section tunnels have always restricted the progress of tunnel construction and even the operation of the entire project. When this kind of tunnel is being built in China, the full-section method or the sequential operation method of lower and lower steps is mainly used in the unfavorable geological tunnel sections such as Class V surrounding rocks and faults. The working area is narrow and limited, the stress release cannot be well controlled, timely support and operation flexibility are poor, and the single process takes a long time and needs to be operated in strict order. The previous process directly restricts the implementation of the next process, and the construction progress is slow, immobile, and not flexible. Although the upp...

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide an excavation and support construction method that can quickly pass through weak and unfavorable geological tunnels, so as to overcome the problems of long process time, loose construction organization, slow construction progress and high cost in the prior art. Large deformation of the surrounding rock, inability to close the tunnel face in time, discontinuous tunnel transportation, inflexible construction equipment, etc.

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