A Construction Method for Large-Section Tunnel Crossing Longitudinal Hard-Soft-Hard Stratum

Abstract

The invention discloses a construction method for a large cross-section tunnel passing through longitudinal hard-soft-hard strata. The construction method comprises the following steps that boundariesof the hard-soft-hard strata are determined; upper steps of the two hard rock strata are excavated by blasting, rock pillars are reserved separately, excavation areas are reinforced with feet-lock bolts, and primary supports of the upper steps are constructed separately; the soft stratum in the area where the upper steps are excavated is reinforced; the two rock pillars are removed, and temporarysupports are constructed; an upper step of the soft stratum is excavated, and primary supports are constructed and a bottom reinforcing layer is reserved; lower steps of the two hard rock strata areexcavated by blasting, rock pillars are reserved separately, excavation areas are reinforced with feet-lock bolts, and primary supports of the lower steps are constructed separately; the soft stratumin the area where the lower steps are excavated is reinforced; the two rock pillars and the temporary supports are removed, a lower step of the soft stratum is excavated, bottom primary supports, an inverted arch and a second lining are constructed, and construction joints are reserved; and the construction steps are repeated until the tunnel construction is completed. According to the construction method for the large cross-section tunnel passing through the longitudinal hard-soft-hard strata, the construction risk is reduced greatly, and social and economic benefits are remarkable.

Description

Technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a construction method for a large-section tunnel passing through a longitudinal hard-soft-hard stratum. Background technique [0002] With the acceleration of the urban construction process, underground spaces that have little impact on ground transportation and the environment are increasingly favored, especially large-section underground space structures that can meet different functions. The construction of large-section tunnels will inevitably encounter more complicated geological conditions, especially in the construction of longitudinal hard-soft-hard stratum tunnels. The weak stratum in the middle is often due to insufficient stability of the surrounding rock, resulting in uneven settlement and large areas of initial support. Problems such as damage to the sprayed concrete, cracking of the shotcrete. However, the existing tunnel construction technology still has no...

AI Technical Summary

Problems solved by technology

However, in the existing tunnel construction technology, there is still no safe and efficient construction method for vertical hard-soft-hard formations. The complex geological conditions have brought great difficulties to the construction of large-section tunnels, resulting in cumbersome construction and difficult control of surrounding rock stability. And endanger the safety of personnel and tunnel structure

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