Construction method of tunnel crossing high-angle thrust water-rich sand-rich fault

Abstract

Disclosed is a construction method for a tunnel passing through a high-angle thrust water-rich and sand-rich fault, comprising the following steps: 1, performing the preliminary excavation and the supporting construction of a rear-side tunnel section (3); 2, performing the synchronous excavation and the supporting construction of the rear-side tunnel section (3) and a drainage cave body of a drainage cave (2); 3, performing the synchronous excavation and the supporting construction of the rear-side tunnel section (3), the drainage cave body of the drainage cave (2), and a rear-side detouring heading pit (1) section; 4, performing the excavation and the supporting construction of a front drainage cave (2) body, a front heading pit section, and a central tunnel section (5); and 5, performing the excavation and the supporting construction of a front-side tunnel section (4). The water on the upper wall of the fault is drained by means of a high-level drainage cave between a tunnel main cave and a detouring heading pit, and the auxiliary drainage is performed by means of the detouring heading pit and the fault condition in front of a tunnel face of the main cave is explored in advance, thereby ensuring the construction safety of each tunnel face. The method employs a three-step method for the excavation of the tunnel main cave, employs double preliminary supporting structures for the full-section supporting of a tunnel cave after excavation, can ensure the safety of the tunnel structure later, and shortens the construction cycle.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a construction method for a tunnel crossing a high-angle thrusting water-rich and sand-rich fault. Background technique [0002] The fault fracture zone refers to the relative movement of the two disks of the fault and the mutual extrusion, which breaks the nearby rocks and forms a fracture zone roughly parallel to the fault plane, referred to as the fault zone. In China, high-angle thrust faults with a cross-sectional dip greater than 45° or 30° are called thrust faults. It is very difficult to construct tunnels that cross high-angle thrust faults. The above-mentioned high-angle thrust faults refer to thrusts with a cross-sectional dip greater than 60° Fault. Especially when the formation is rich in water and sand, the construction is more difficult. Water-rich and sand-rich formations are also called water-rich sand formations, which refer to formation...

AI Technical Summary

Problems solved by technology

In water-rich and sand-rich strata, rock mass fragmentation provides more favorable conditions for the occurrence and enrichment of groundwater, and the construction is very difficult. In addition, the stratum contains sand layers, and water and sand gushes are prone to occur during construction. In addition, The dip angle of the fault section is greater than 60°, which is likely to cause catastrophic consequences and seriously affect the safety and efficiency of construction

Therefore, when the tunnel crosses a fault that is rich in groundwater, the rock mass is mostly clastic rock, and is rich in sand and gravel at a high angle and thrusts against a water-rich and sand-rich fault, the construction risks are very high. When the water-rich thrust fault is at an angle, under the action of high water pressure, geological disasters such as water gushing and sand gushing are very likely to occur suddenly on the working face, and the construction risk is high, the construction is difficult and the construction progress is slow

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