金丽温高速公路连拱隧道超挖预测及原因分析

通过对金丽温高速公路连拱隧道的地质特征进行现场调查,经分析得出隧道区岩体结构面的特征参数,利用分析出的结构面特征参数值,结合隧道超挖预测中的神经网络理论及结构面网络模拟理论,对连拱隧道的超挖情况进行预测。从分析结果看,超挖问题在连拱隧道的施工过程中不可避免,其产生部位主要集中在中导洞与隧道的连接部位,通过预测得出的结果与现场开挖情况进行对比分析说明,隧道的超挖预测理论预测结果与实际有较好的一致性,文中最后针对隧道的特点,分析了产生超挖的基本原因,为确保隧道开挖过程中减少超挖提供依据。

Forecast of overbreak and analysis of cause of formation in double-arch tunnels in Jinliwen highway

Based on the field investigation of geological characteristics of double-arch tunnel in Jinliwen highway,the characteristic parameters of rock mass discontinuity plane in the tunnel are analyzed and obtained. According to neural network and discontinuity plane network mapping theory of forecast of overbreak, overbreak of double-arch tunnel is forecasted by use of the discontinuity plane characteristic parameters. The result shows that overbreak is an inevitably problem in double-arch tunnel construction, and overbreak location of double-arch tunnel lie mainly at the pontes of tunnel and middle tunnel. The contrasts of forecast result and result of excavation in situ for overbreak of double-arch tunnel shows that the basic theory of tunnel overbreak can ensure the veracity of forecast result. Aimed at the character of double-arch tunnel, the basic reason of bringing to overbreak is analyzed. It offered a basis for decreasing overbreak during tunnel excavation.