Construction method of large-cross section loess tunnel cave entering shallow buried section

Abstract

The invention relates to a construction method of a large-cross section loess tunnel cave entering shallow buried section. The construction method comprises the following steps of: (1) firstly performing excavation protection on a face-upward slope before the cave entering construction; (2) after the face-upward slope construction in the cave entering position is completed, building a reinforced concrete guide wall; (3) after the construction of the guide wall is completed, beating a long pipe roof for forepoling; (4) constructing a leading conduit for supporting on the basis of the big pipe roof forepoling by matching a sectional-steel steel frame; and (5) using a few-part and ultra-short-step excavation construction method for constructing a tunnel, reinforcing monitoring and measurement during the construction and timely constructing primary supporting and secondary lining. The method has the advantages that the influence of tunnel excavation deformation on the ground surface can be effectively reduced; the tunnel excavation stability of the cave entering shallow buried section is ensured; the construction progress is accelerated; the technical problem of construction of the large-cross section loess tunnel cave entering shallow buried section is solved; the tunnel construction safety is ensured; meanwhile, the investment is reduced; and the economic benefits are improved.

Description

technical field [0001] The invention relates to the field of tunnel construction, in particular to a construction method for a shallow-buried section of a large-section loess tunnel. Background technique [0002] With the implementation of the country's western development strategy, the construction of transportation infrastructure in the western region has achieved unprecedented development. Expressways and railways are rapidly extending to the western region, and more and more traffic tunnels will pass through the western loess region. Loess, as a continental sediment accumulated in the Quaternary system, has the characteristics of large pores, vertical joints and tubular channels. The soil particles are easy to disintegrate when exposed to water, showing strong collapsibility. Loess tunnels are prone to landslides and large deformations during the excavation of loess tunnels. Improper construction methods for shallow-buried loess tunnels can also cause surface subsidence,...

AI Technical Summary

Problems solved by technology

Loess tunnels are prone to landslides and large deformations during the excavation of loess tunnels. Improper construction methods for shallow-buried loess tunnels can also cause surface subsidence, which greatly increases the difficulty of tunnel construction in the area.

Although the traditional double-side wall pilot pit method can solve the safety of tunnel construction, its construction is complicated, the construction period is long, and the cost is high; Construction Safety of Sectional Loess Tunnel

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