| Huashigou tunnel of Shibai highway is a separate long tunnel, the tunnel is located inthe middium to high mountain areas in southwest of Hubei, the geology and topographycondition is extremely complex. The length is2142m and the maximum depth is about253m of this tunnel. Because of the excavation in slope toe, the airport surface was formedin the bottom edge of slope and the resurrection of the landslide was induced, then in June2010sliding occurred and dehiscence appeared on surface, and tunnel construction in exitpart had been influenced seriously.To ensure the construction and the stability of tunnel portal, the paper based on thescience and technology project of Hubei communications department landslide evolutioncharacteristics under the condition of environmental change and engineering activities andprevention and control technology, and relied on Shibai highway Huashigou tunnelengineering. As the domestic and foreign research results and related information aresummarized and analyzed, and on the basis of field geological survey, in situ test,laboratory test, the theoretical analysis and numerical simulation, so the numericalsimulation of tunnel excavation in the condition of landslide geological and dynamicstability analysis of tunnel portal slope are taken.（1） According to the field engineering environment, scoping work is taken, at the sametime geotechnical geological parameters test in the field （bulk density test, direct sheartest）are conducted, then the work content is conclude and provided for similar engineeringgeology inspection and field test in the future.（2） Based on domestic and foreign researches of slope engineering, landslide slopeengineering theories are synthesized and studied, then the slope failure mechanism andfailure mode are analyzed.（3） By FLAC3Dnumerical simulation analysis model of tunnel portal excavationconstruction is set up, then the influence of the slope under the period of tunnel excavationis studied and the vaults, waists deformation and slope displacement are monitored, at lastthe mechanical behavior and deformation rules of the tunnel portal and slope are studied. （4） Based on shear strength reduction method, by FLAC3Dthe tunnel portal slopesafety factor numerical simulation analysis model is set up, then the slope safety factorsare calculated under the condition of before and after the slope foot cutting and differentreinforcement methods, at last the causes of slope damage are analyzed and an effectiveslope reinforcement method is put forward. |
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