Protection structure for rapidly entering semi-cutting single-pressure open cut tunnel and construction method

Abstract

The invention discloses a protection structure for rapidly entering a semi-cutting single-pressure open cut tunnel and a construction method. The construction method comprises the following steps of S1, construction preparation; S2, construction of a slope top intercepting ditch; S3, side and back slope excavation and support; S4, construction of a bias wall foundation and a lower wall body; S5, construction of a cover arch and a pipe shed; S6, construction of a back haunch fillet of arch of the open cut tunnel; S7, construction of an upper wall body of a bias wall; and S8, hidden tunnel excavation and primary support, wherein after construction of the back haunch fillet of arch is completed, according to the advanced geological forecast and monitoring measurement result, a reserved core soil three-step partial excavation method is adopted for construction, hidden tunnel soil body is excavated, after construction of an inverted arch primary support is completed, the inverted arch primary support and the back haunch fillet of arch are closed into a ring, tunnel construction is completed, and smooth tunnel entering is achieved. According to the method, damage of vegetation at the opening of the tunnel is avoided, the construction period is saved, the construction cost and the safety risk are reduced, good social benefits are generated, and on the premise that the construction safety of the ecological environment is guaranteed, the problem of difficulty in entering of the semi-cutting single-pressure tunnel is effectively solved.

Description

technical field [0001] The present invention relates to a construction method for rapid tunnel entry, in particular to a half-cut single-pressure open tunnel rapid entry protection structure and construction method, which is mainly suitable for half-cut single-pressure open tunnels under special mountain terrain The utility model relates to rapid tunnel entry construction of highways and railway tunnels, which can also be used for tunnel constructions similar to highways and hydraulic engineering, and belongs to the technical field of tunnel construction. Background technique [0002] With the continuous expansion of expressway construction in my country, the high-speed development of the Yunnan-Guizhou-Sichuan plateau area is driven, and the number of plateau mountain tunnels is increasing. The complexity, particularity and limitations of the plateau mountain terrain greatly increase the difficulty of mountain tunnel construction. Safe tunneling often becomes the focus and d...

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Problems solved by technology

[0006] In view of the problems of slow entry speed, long construction period, high construction cost, and large environmental pollution in the above-mentioned traditional construction methods, and large-scale excavation is adopted, and then the slope is protected, the construction method seriously damages the original landform and the natural nature of the mountain stability, also increases the construction cost, and in the process of excavation, it is prone to cracking and instability of the side slope, causing accidents such as landslides and collapses, and there are many defects and deficiencies such as serious hidden dangers, which are improved by the present invention And innovation, the purpose is to provide a construction principle that can follow the "zero excavation" and "early entry, late exit", do not dig too much, make full use of the self-stability of the existing mountain topography, and realize the avoidance of side-to-side Such a half-cut single-pressure type open-hole tunnel rapid entry protection structure and construction method that protects too much upside slope and reduces the risk brought by high slope

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