块体理论在高速公路连拱隧道超挖预测中的应用

Application of block theory on overbreak forecast in double-arch tunnel

通过对金丽温高速公路连拱隧道区的结构面特征进行现场调查,经统计分析得出结构面的特征参数,利用分析出的结构面特征参数值,结合块体理论,对连拱隧道的超挖情况进行预测。首先介绍了块体理论在超挖预测中运用的基本方法,推导了最大块体体积的计算公式,通过编制的计算程序对金丽温高速公路2个连拱隧道的超挖块体大小及位置进行预测。从分析的结果看,超挖问题产生部位主要集中在中导洞与隧道的连接部位,预测的结果与实际情况基本一致。通过预测得出的结果证实了块体理论在高速公路连拱隧道超挖预测中的适用性。

The discontinuity plane characteristics of doubled arch tunnel in Jinliwen highway is investigated in situ. The characteristic parameters of rock mass discontinuous in the tunnel are got by use of statistical analyzing. According to block theory, overbreak of doubled arch tunnel is forecasted by use of the analyzed discontinuity plane characteristic parameters. Firstly, the basic method of application of block theory is introduced. The calculation equation of maximum block volume is gained. The location and block volume of overbreak for three doubled arch tunnels are forecasted by use of calculation program. The result shows that overbreak location of doubled arch tunnel lie mainly the pontes between tunnel and middle tunnel. The result of forecasting is consistent with the fact one. The applicability of block theory in overbreak of doubled arch tunnel is tested.