地下水对董志塬黄土隧道工程性质的影响分析

地下水对新建隧道工程具有诸多不良影响,通过现场调研和资料整理,对董志塬区黄土地层性质和地下水分布特征进行系统总结,分析董志塬地下水对银西高铁隧道工程的影响。结果表明:(1)董志塬区黄土物理力学性质随地层岩性、位置和地下水位变化存在一定的差异性,含水率和液性指数从塬边南部向塬边北部依次减小,孔隙比和压缩模量从塬边南部向塬边北部依次增大;(2)董志塬区地下水位埋深在塬心浅而塬边深,北塬地下水位埋深略比南塬深;含水层厚度则在塬心比较厚,而向塬边逐渐减小;(3)董志塬区地下水对银西高铁黄土隧道工程的主要不良影响有:引发黄土湿陷性;形成软塑状黄土;导致隧道管涌、涌水、塌方、冒顶事故等。

Analysis of the Influence of Groundwater on Engineering Property of Loess Tunnel in Dongzhiyuan Region

Groundwater has many negative effects on the construction of newly built tunnels. The properties of loess strata and the characteristics of groundwater distribution are summarized based on field investigations and analysis of experimental data,and the influence of groundwater on engineering property of loess tunnel in Dongzhiyuan regions is analyzed. The results show that:( 1) there are some differences in the physical and mechanical properties of loess in Dongzhiyuan region with respect to lithology,geographical position and groundwater level,the water content and liquid index decrease from the southern margin to the northern margin,the void ratio and compression modulus increase from the southern margin to the northern margin;( 2) the groundwater depth of the middle plateau of Dongzhiyuan region is higher than that of the margin,and the groundwater depth of the northern margin is slightly deeper than that of the southern margin; the aquifer thickness is thick on the middle plateau,but gradually decreases on both margins.( 3) the negative influences of the groundwater on the engineering property of loess tunnel in Dongzhiyuan region mainly include the followings: loess collapsibility,soft plastic loess; accidents of tunnel piping,water flowing,caving and roof falling caused by unsmooth seepage and excretion of groundwater.