隧道出口段环保型结构稳定性分析

Stability analysis of environmental protection structure on exit of tunnel

随着国民经济的发展和社会的进步,公路隧道环保型建设技术日益受到重视。以江苏宁(南京)淮(安)高速公路南京江北段老山公路隧道为依托,提出了隧道出口傍山段的一种新型环保结构——棚洞结构。采用有限元强度折减法研究该隧道出口段边坡与整个支挡结构的稳定性。通过最危险段的分析表明:该新型结构将傍山边坡的锚喷支护与棚洞结构有机结合起来,形成完整的受力体系与环保型边坡支挡结构,是安全合理的。在路线走廊困难地段、沿河岸沟谷地、路线傍山布置地段,构造物应顺应地形,提倡设置棚洞、半隧道结构,达到保护边坡和自然环境的目的。

More and more attention has been focused on the study of construction technology of highway tunnel considering environmental protection with the developing of national income and social advancement. Based on the actual conditions of Lao-shan highway tunnel in Nanjing, a shed-tunnel structure which is an environmental protection structure for the outlet of tunnel adjacent to mountain, is suggested. The stability of this new structure has been studied by means of FEM simulation with reduction of the soil strength. The following conclusions can be drawn from the computation results of the most dangerous zone: combining anchor-shotcrete with shed-tunnel structure, a reasonable complete supporting system of the slope was formed, and the whole slope with shed-tunnel structure is safe too. The structure which is adopted according to the natural topography, such as shed-tunnel or half-tunnel, should be adopted to protect the natural environment and slope in the complicated zone, for example, the slope adjacent to mountain.