A construction method for tunnels in upper soft and lower hard strata

Abstract

The invention discloses a construction method for a tunnel in an upper-soft and lower-hard stratum. When constructing any one of the tunnels to be constructed, the steps include: 1. Excavation of the rear tunnel section and initial support construction; 2. Tunnel at the junction Reinforcement of the surrounding rock of the section and temporary reinforcement of the rear tunnel section; 3. The removal of the temporary support of the tunnel arch; 4. The forward movement of the shield machine and the construction of the second lining of the tunnel; 5. The construction of the shield. The invention is reasonable in design, simple in construction and good in use effect. The structure stability of the rear tunnel section is ensured through the temporary support of the tunnel arch, and the surrounding rock of the tunnel section at the junction is repaired by combining surface grouting reinforcement with internal reinforcement. Effective reinforcement can effectively improve the mechanical properties of the surrounding rock, effectively ensure the safe construction of the tunnel, and effectively reduce the ground subsidence caused by excavation; after the reinforcement of the surrounding rock in the tunnel section at the junction is completed, the temporary support of the tunnel arch will be carried out. Remove and move the shield machine forward to construct the front tunnel section, 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 for 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 building tunnels by excavating underground tunnels. A construction method for excavating sections to build tunnels and underground works. The shield method is a fully mechanized construction method in the construction of the underground excavation method. It pushes the shield machine in the ground, and supports the surrounding rocks through the shield shell and segment to prevent the collapse into the tunnel; In front of the excavation front, a cutting device is used to excavate the soil, which is transported out of the hole by an excavation machine, and is pushed in by a jack at the rear, and prefabricated concrete segments are assembled to form a mechanized const...

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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