Debris flow formation tunnel excavation construction method and structure

Abstract

The invention discloses a debris flow formation tunnel excavation construction method. The method comprises the following steps that S1, geological conditions nearby a tunnel face are detected, and the position and scope of a debris flow cavity on a to-be-excavated tunnel main hole path are determined; S2, an energy-releasing and pressure-reducing hole is formed nearby the debris flow cavity and is made to meet process conditions for releasing debris flow potential energy of the debris flow cavity; S3, the debris flow cavity is opened by means of the energy-releasing and pressure-reducing hole, the debris flow potential energy in the debris flow cavity is released, and the energy-releasing and pressure-reducing hole is closed after the potential energy is released; S4, a circuitous guide hole is formed in one side of a tunnel main hole, and a plurality of working faces are formed on the to-be-excavated tunnel main hole path; and S5, the rest of the tunnel main hole is constructed. The invention further discloses a debris flow formation tunnel excavation construction structure. By means of debris flow cavity characteristics, the high-pressure potential energy in the debris flow cavity is fully released in advance, and safety of construction in front of the tunnel face is guaranteed.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a construction method and structure for tunnel excavation in a debris flow formation. Background technique [0002] Before the excavation of the main tunnel, the geological conditions are generally used as the main basis, and the construction period, tunnel length, construction technology level and other factors are comprehensively considered to select a feasible excavation method. Common tunnel construction methods include the full-face excavation method, the new Austrian method, the pilot pit advance + expansion method, etc. However, the above construction methods are not applicable to the main tunnel passing through the debris flow formation. This is because the debris flow formation is a special geological structure, commonly known as underground debris flow. Among them, the clastic fluid mainly contained in the clastic flow formation is plastic fluid, which is ...

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Problems solved by technology

However, this construction technology only discharges the water in the debris flow. Since the debris flow is a fluid with very high pressure, which also contains solid substances such as silt, gravel, and clay, it can only be discharged through high-level drainage. In this way, the potential energy of high-concentration and high-density debris bodies stored in the debris flow formation cannot be effectively released, which makes it difficult for the advanced support and initial support made during tunnel construction to effectively support the tunnel, and it is easy to Caused large-scale collapse of the rock mass at the face of the tunnel

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