TBM pilot tunnel expansion digging method for 20km double-line double-cavity ultra-long tunnel construction

Abstract

The invention provides a TBM pilot tunnel enlarging excavation method which is adopted in 20km dual-line dual-tunnel super-long tunnel construction, belonging to the building technical field of road, railway or bridge. The method is that a. two TBMs respectively with the diameters of 4.2m and 3.5m are adopted so as to excavate from the bottom center of the lower-end tunnel opening of the two parallel tunnels to the high-end direction of the tunnel to form two pivot tunnels A and B; b. enlarged excavation and lining operation are firstly carried out in the B pivot tunnel which passes through a tunnel-typed ventilation air exchange system and a communicated track delivering system which consist of the A pivot tunnel and a transverse passage; c. after the pivot tunnel A and the pivot tunnel B are interpenetrated, only two coal faces at the inlet and the outlet of A line are arranged; d. after the enlarged excavation in B line is completely achieved, 8-10 coal faces are opened to achieve the enlarged excavation of the A line. The invention has the advantages of fast construction speed, small construction operation quantity, economics and safety, has no damages or effects to the plants out of a mountain body, damaging slightly the self-flowing water system which is formed in the mountain body and protecting the around environment of the construction.

Description

technical field [0001] The invention belongs to the technical field of construction of roads, railways or bridges. Background technique [0002] At present, the traditional construction method for extra-long double-lane double-cavity tunnels of about 20 km is to use auxiliary pilot pits to form long tunnels and short tunnels. Auxiliary guide pits generally have several main forms such as vertical shafts, inclined shafts, horizontal guides, and horizontal holes. The surface vegetation is damaged to a certain extent, the surrounding environment is affected, and the balance of hydrogeological conditions is broken. In my country, since the 1990s, large-diameter TBMs have been successively applied in hydraulic engineering projects, and good results have been achieved. However, there is no precedent in various domestic construction fields for using TBMs to open pilot holes first and then drill and explode. . At present, more than a dozen extra-long tunnel auxiliary pilot pits ha...

AI Technical Summary

Problems solved by technology

Auxiliary guide pits generally have several main forms such as vertical shafts, inclined shafts, horizontal guides, and horizontal tunnels. However, no matter what the form is, it requires a lot of investment in people, money, and materials, and the construction cost is very high. The surface vegetation is damaged to a certain extent, the surrounding environment is affected, and the balance of hydrogeological conditions is broken

In my country, since the 1990s, large-diameter TBMs have been successively applied in hydraulic engineering projects, and good results have been achieved. However, there is no precedent in various domestic construction fields for using TBMs to open pilot holes first and then drill and explode.

At present, more than a dozen extra-long tunnel auxiliary pilot pits have been completed or are under construction in my country. The original stress state and hydrological conditions of the entire mountain have been destroyed, which has brought hidden dangers of desertification.

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