Surrounding rock reinforcement method for junction tunnel section in upper-soft lower-hard stratum constructed adopting shield method and mining method

Abstract

The invention discloses a surrounding rock reinforcement method for a junction tunnel section in an upper-soft lower-hard stratum constructed adopting a shield method and a mining method. The method comprises the steps that 1, tunnel face grouting reinforcement is carried out, specifically, grouting reinforcement is carried out on stratum in front of an excavation face of an upper tunnel body by adopting grouting pipes; 2, junction surface grouting reinforcement is carried out, specifically, grouting reinforcement is carried out on the reinforced stratum by adopting sleeve valve pipes; 3, tunnel arch part advanced support is carried out, specifically, advanced support is carried out on an arch part of the junction tunnel section; 4, grouting pipe removal is carried out; and 5, tunnel faceplugging is carried out, specifically, a tunnel face is plugged through concrete backfilling, and a tunnel face plugging structure is obtained. The method is reasonable in design, simple and convenient to construct and good in use effect, and surrounding rock of the junction tunnel section is effectively reinforced by the method of combining the surface grouting reinforcement with the in-tunnel reinforcement so that the mechanical property of the surrounding rock can be effectively improved; and the tunnel face of the junction tunnel section is reliably plugged before and after reinforcement so that tunnel safety construction can be effectively guaranteed, and ground settlement caused by excavation can be effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a method for reinforcing the surrounding rock of a tunnel section at the junction of the upper soft and lower hard stratum shield method and the mining method. 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 ...

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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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