Drainage device and method suitable for excavation of tunnel steps in water-rich soft rock stratum

Abstract

The invention relates to a drainage device and method suitable for water-rich soft rock stratum tunnel step excavation. The drainage device comprises a drainage ditch and a drainage pipe. The drainage ditch is arranged at the lower step, drainage pipes are arranged in the lower step in the horizontal direction, the drainage pipes are arranged on the two sides of the drainage ditch and communicated with the drainage ditch, and the drainage pipes are provided with water inlet holes so as to collect accumulated water in the lower step and converge the accumulated water in the drainage pipes through the drainage ditch so that the accumulated water can be drained conveniently. When the tunnel is excavated through the up-and-down step method, drainage of the stratum at the lower step can be achieved, softening of rock-soil mass on the upper surface of the lower step caused by underground water deposition is avoided, instability and collapse of a tunnel primary support are avoided, and secondary lining of the tunnel is achieved conveniently.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a drainage device and method suitable for tunnel step excavation in water-rich soft rock formations. Background technique [0002] The geology of water-rich and low-strength soft rock is mostly silty mudstone, strongly weathered rock formation, extremely soft, extremely low compressive strength, poor cohesive force, extremely unstable, and the water strength is greatly reduced. Therefore, the excavation of water-rich and low-strength soft rock formations often uses the upper and lower bench excavation method, thereby reducing the deformation of the tunnel surrounding rock. [0003] The inventor has learned that after the excavation of the upper steps is completed, groundwater often seeps into the lower steps and deposits on the surface of the lower steps, thereby deteriorating the construction environment. Under the action of immersion, the rock and soil ...

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Problems solved by technology

[0003] The inventor has learned that after the excavation of the upper steps is completed, groundwater often seeps into the lower steps and deposits on the surface of the lower steps, thereby deteriorating the construction environment. Under the action of immersion, the rock and soil soften, which may easily lead to the instability and collapse of the primary support; and the soil in the water-rich and low-strength soft rock formation is weak, and the lost fine particles are easy to block the drainage pipes, and the long-term drainage effect is poor

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