Construction method of circuitous pilot tunnel for preventing and treating water inrush of tunnel

Abstract

The invention discloses a construction method of a circuitous pilot tunnel for preventing and treating water inrush of a tunnel. The circuitous pilot tunnel adopts a trackless transportation single-lane V-level composite section, the deformation reserve is 15cm, I-shaped steel is adopted for reinforcing supporting. The construction method comprises the following steps of carrying out treatment before construction; carrying out excavating and tunneling by a bench cut method; carrying out supporting construction; carrying out advance supporting; spraying concrete; and constructing side wall drain holes of the circuitous pilot tunnel. According to the construction method of the circuitous pilot tunnel for preventing and treating the water inrush of the tunnel, supporting of corresponding maintunnel arch frames at the junction of a main tunnel and the top of the circuitous pilot tunnel is strengthened so that the structural strength of the tunnel can be improved; excavation and tunnelingare carried out through the bench cut step method so that construction interference can be avoided, and construction risks are reduced; through supporting construction, scattered water can be guided and drained to side ditches in a centralized mode, so that the construction quality of spraying the concrete is improved; and through the construction of the side wall drain holes of the circuitous pilot tunnel, the effects of drainage and pressure reduction can be quickly achieved, and the risk of the water inrush of a tunnel face during construction is effectively reduced.

Description

technical field [0001] The invention relates to the technical field of tunnel water inrush construction, in particular to a construction method for preventing tunnel water inrush and a circuitous guide pit. Background technique [0002] Longnan Tunnel is a controllable and difficult project on the whole line. The total length of the tunnel is 10.24km, the maximum buried depth is 580m, and the minimum buried depth is 16m. 4 working areas and 5 working faces organize construction. The geological lithology is mainly composed of granite and sandstone, and a total of 11 faults are crossed. Among them, the DK99+500~+620 section is the F8 regional large fault fracture zone, with a length of 120m and a water pressure of 0.5MPa in the cave body. There are dangerous rocks in the cave body There are many risks such as rockfall, mud gushing, rock burst, high ground temperature, karst, shallow burial, surrounding rock instability and landslides, etc. The maximum water inflow is 18,000 c...

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Problems solved by technology

[0003] Although the current existing methods for preventing water inrush from the face of tunnels in karst water-rich strata can discharge the water in the fault to a large extent, it will greatly disturb the surrounding rock in the area, increase investment costs, and prolong the construction period. Therefore, it is urgently needed Improve

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