Tunnel construction method for passing through boundary strata of earth and stone

Abstract

The invention discloses a tunnel construction method for passing through the boundary stratum of earth and stone. The tunnel construction method comprises the following steps: I, excavation of a reartunnel segment and initial supporting construction; II, excavation of a middle tunnel segment and initial supporting construction; III, excavation of a front tunnel segment and initial supporting construction, wherein the rear tunnel segment, the middle tunnel segment and the front tunnel segment are all three-step synchronous excavated tunnel segments; and in the process of excavation from rear to front, constructing the secondary lining of the tunnel on the inner side of the initial supporting structure of the constructed tunnel from rear to front. The tunnel construction method has the advantages of reasonable design, simple construction and good use effect. The tunnel construction method selects an appropriate drilling and blasting method according to the position relationship betweenthe earth and stone interface and a tunnel hole, adopts a three-step synchronous excavation way to carry out blasting excavation, can ensure the safe and reliable excavation process of the tunnel passing through the boundary stratum of earth and stone, and can ensure the stable structure of the tunnel. Moreover, in the excavation process, the initial supporting structure and the secondary lining of the tunnel are adopted to provide stable and reliable supporting for the large-section tunnel.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a tunnel construction method for crossing soil-rock boundary strata. Background technique [0002] In the construction process of railway and highway tunnel projects, due to the limitation and influence of geological conditions, it will cause great influence and difficulties to the construction during the construction process. In the process of tunnel construction, various combinations of rock formations are often encountered, such as weak and uneven surrounding rock, shallow buried bias landform, soil-rock mixed geology and so on. For the excavation and support of tunnels that pass through soil-rock mixed strata (also known as soil-rock interface geology or soil-rock boundary strata), at present, the main methods in China are advanced pipe shed grouting support, advanced horizontal jet grouting pile reinforcement, and controlled excavation footage. and o...

AI Technical Summary

Problems solved by technology

During the actual tunnel construction, the main problems of tunnel excavation in the soil-rock boundary stratum are as follows: first, the hardness of the rock and soil is not uniform, and the blasting of the weathered rock layer in the lower part will easily cause the upper soil layer to collapse, which is harmful to the construction personnel; second, the groundwater The enrichment area further softens the soil-rock boundary strata, causing serious deformation of the surrounding rock; third, the swelling of the expansive soil with water causes the primary support to deform and crack, and in severe cases, the deformed structure of the primary support arch will be damaged and the support capacity will be lost

Once the corresponding reasonable support measures are not adopted in the actual construction or the excavation method is improper, it is very likely to cause deformation of the support in front of the face of the tunnel, and even serious consequences of collapse

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