A construction method of circuitous guide pit for prevention and control of tunnel water inrush

Abstract

The invention discloses a construction method of a circuitous guide pit for preventing water inrush in a tunnel. The circuitous guide pit adopts a grade V compound section of a trackless transport single lane, the reserved amount of deformation is 15 cm, and I-shaped steel is used to strengthen the support. It also includes the following steps: Pre-construction treatment; step method excavation; support construction; advance support; shotcrete; construction of weep holes on the side wall of the circuitous pilot pit. The construction method of the circuitous guide pit for preventing water inrush in the tunnel of the present invention can improve the structural strength of the tunnel by strengthening the support of the arch frame corresponding to the main tunnel at the junction of the main tunnel and the top of the circuitous pilot pit, and can avoid construction by excavating through the step method. Interference and reduce construction risks. Through support construction, scattered water can be concentrated and drained to side ditch, improving the quality of sprayed concrete construction. Through the construction of drainage holes on the side wall of the pilot pit, the effect of drainage and pressure reduction can be quickly achieved, effectively reducing the construction cost. There is a risk of water gushing on the working surface.

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...

AI Technical Summary

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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