Construction method for tunnel passing through high-angle thrust water-rich and sand-rich fault

Abstract

The invention discloses a construction method for a tunnel passing through a high-angle thrust water-rich and sand-rich fault. The method comprises the steps: 1, performing the preliminary excavationand the supporting construction of a rear tunnel segment; 2, performing the synchronous excavation and the supporting construction of the rear tunnel segment and a water drainage hole body of a waterdrainage hole; 3, performing the synchronous excavation and the supporting construction of the rear tunnel segment, the water drainage hole body of the water drainage hole and a rear detouring headingsegment; 4, performing the excavation and the supporting construction of a front water drainage hole body, a front heating segment and a central tunnel segment; 5, performing the excavation and the supporting construction of a front tunnel segment. According to the invention, the water on the upper wall of the fault is drained through a high-level water drainage hole between a tunnel front hole and a detouring heading pit, and the auxiliary water drainage is performed through the detouring heading pit, and the fault condition in front of the tunnel face of the front hole can be explored in advance, thereby guaranteeing the construction safety of each tunnel face. The method employs the three-step method for the excavation of the tunnel front hole, employs double preliminary supporting structures for the full-section supporting after excavation, can guarantee 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, in particular to a construction method for a tunnel passing through 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 discs of the fault, squeezing each other, so that the nearby rocks are broken, forming a fracture zone roughly parallel to the fault plane, referred to as the fault zone. In China, high-angle thrust faults with a cross-section dip angle greater than 45° or 30° are called thrust faults, and tunnel construction through high-angle thrust faults is very difficult. fault. Especially when the formation is rich in water and sand, the construction is more difficult. Water-rich sand stratum, also known as water-rich sand stratum, refers to the stratum that is rich in groundwater and contains sand layers, which are both water-rich strata and sand-rich strata. In the water-ric...

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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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