隐伏岩溶洞群对公路隧道顶板承载力影响的研究

Research on Influence of Concealed Karst Caverns on Bearing Capacity of Top Plate of Highway Tunnel

针对西南地区岩溶隧道的实际工程,开展了隐伏岩溶群对公路隧道顶板承载力影响的三维数值敏感性分析研究。经对岩溶顶板稳定性影响因素分析,选择溶洞顶板厚度、顶板岩体的工程地质特性(定量指标为岩体的力学参数)、溶洞的宽度、溶洞高度、上覆土层厚度为影响溶洞顶板稳定性的五个主要影响因素作为影响因子,进行正交敏感性数值试验。根据影响因素敏感度的正交三维有限元法分析结果得出,影响顶板承载力和顶板中心下沉位移大小顺序依次为:岩体力学参数、顶板岩层厚度、覆盖土层厚度、溶洞宽度、溶洞高度。

Based on a tunnel real engineering of southwest region, a three dimensional numerical analysis concerning the sensitivity influence of the concealed karst caverns on the bearing capacity of the top plate of the highway tunnel was carried out. Through the stability analysis of influence factors on top plate of tunnel, five main influence factors on the stability of top plate, including the thickness of top plate, the geological properties of roof rock mass （the quantitative indexes are the mechanical parameters of rock mass）, the width of karst caverns, the height of karst caverns and the thickness of overlay rock mass, were selected for orthogonal sensitivity numerical analysis. The result of FEM orthogonal sensitivity numerical experiment indicates that the degree sequence of the influence factors on the bearing capacity and subsidence displacement of the top plate is the properties of rock mass, the thickness of top plate, the thickness of overlay rock mass, the width of karst caverns and the height of karst caverns.