高速公路连拱隧道超挖预测及评价研究

STUDY ON FORECASTING AND EVALUATION OF OVERBREAK IN DOUBLE-ARCH TUNNELS OF HIGHWAY

通过对金丽温高速公路红枫连拱隧道区的结构面地质特征进行详细分析和现场调查,得出隧道区岩体结构面的特征参数值,在超挖预测中的结构面网络模拟理论及块体理论基础上,利用分析得出的结构面特征参数值对连拱隧道超挖情况进行预测,同时,预测不同块体体积出现的概率以及块体在连拱隧道中可能出现的部位。从分析结果看,连拱隧道的超挖部位主要分布在中导洞与隧道的连接部位;在结构面连通性较好的情况下,在隧道的侧边墙同样会出现较大方量的超挖。最后对隧道超挖预测的结果与现场开挖情况进行对比分析,分析连拱隧道超挖产生的原因,通过验证得出连拱隧道超挖预测的结果与实际结果具有较好的一致性,为连拱隧道的合理开挖提供理论基础。

The geological characteristics of discontinuity plane of Hongfeng doubled arch tunnel in Jinhua— Lishui—Wenzhou highway are investigated and analyzed to obtain the characteristic parameters.Based on discontinuity plane mapping theory and keyblock theory,the overbreak of doubled arch tunnel is forecasted by using the analytical discontinuity plane characteristic parameters.At the same time,the appearance probability and the location of overbreak block in doubled arch tunnel are forecasted.The result shows that the overbreak location of doubled arch tunnel is located mainly in the connection between tunnel and middle guide tunnel.Under the condition of good connectivity of discontinuity,a great quantity of overbreak on side wall may occur.The forecasting and in-situ excavation are contrasted,and the causes of overbreak are analyzed.The good coincidence of forecasting and excavation offers a theoretical basis for the excavation of doubled arch tunnel reasonably.