Tunnel construction method for formation with upper soft part and lower hard part

Abstract

The invention discloses a tunnel construction method for a formation with an upper soft part and a lower hard part. During construction of any one of to-be-constructed tunnels of the construction tunnel, the method comprises the following steps: 1, performing back side tunnel segment excavation and preliminary bracing construction; 2, performing junction tunnel segment surrounding rock reinforcement and back side tunnel segment in-cavity temporary reinforcement; 3, disassembling a tunnel temporary supporting cover arch; 4, enabling a shield tunneling machine to move forwards and performing tunnel secondary lining construction; and 5, performing shield tunneling construction. The method is reasonable in design, simple and convenient to construct and good in use effect; the stability of theback side tunnel segment is guaranteed by a tunnel temporary supporting cover arch; the junction tunnel segment surrounding rock is effectively reinforced by a mode of combining ground surface grouting reinforcement with in-cavity reinforcement, so that the mechanical property of the surrounding rock can be effectively improved, the safe construction of the tunnel can be effectively guaranteed andsurface subsidence caused by excavation can be effectively reduced; and after the junction tunnel segment surrounding rod reinforcement is completed, the tunnel temporary supporting cover arch is disassembled and the shield tunneling machine moves towards in place to perform construction on the front side tunnel segment, so the construction process is safe and reliable.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a tunnel construction method in upper soft and lower hard strata. Background technique [0002] The mining method (also known as the shallow burial method) refers to the construction method of tunnel construction by excavating underground tunnels. The mining method is a tunnel excavation construction method of the underground method, mainly using the drilling and blasting method The construction method of excavating sections to build tunnels and underground works. The shield tunneling method is a fully mechanized construction method in the underground excavation method. It pushes the shield machine in the ground, and supports the surrounding rock through the shield casing and segments to prevent collapse into the tunnel; A mechanized construction method in which the soil is excavated with a cutting device in front of the excavation face, transported out o...

AI Technical Summary

Problems solved by technology

However, the above-mentioned single reinforcement method still cannot guarantee the construction safety of the tunnel section at the junction of the shield tunneling method and the mining method where the surrounding rock is relatively broken and rich in water, and there are the following risks: First, sand and landslide risks: due to the large excavation section , the vault is buried shallowly and the surrounding rock is relatively broken. Under the influence of tunnel blasting construction and direct hole grouting in the cave, it is very easy to cause sand gushing and landslide disasters in the cave; sand gushing and landslides in the cave cause the loss of the stratum above the tunnel, which will cause Developed into surface subsidence, pipeline fracture and damage; second, poor lithology, high risk of water inrush: poor lithology and thicker medium-coarse sand layer in the upper part, low-lying terrain, large water volume, sufficient supply, large confined water, and intrusive water high risk

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