土石交界地质条件下浅埋隧道的开挖反应研究

Study on Excavation Reaction of Shallow Tunnel Under the Boundary Condition of Soil and Rock

不同地质介质交界的复杂地质状况对于隧道工程的开挖建设带来很大困难,土石交界地层是这种地质情况的典型代表。针对该地质条件下的隧道开挖问题,以某浅埋公路隧道为工程背景,展开了不同掘进方向和不同土石界面倾角下的隧道开挖反应数值模拟,对比了不同掘进方向下的隧道开挖反应特征,分析了土石界面倾角对隧道开挖反应的影响。结果显示:不同掘进方向下,在土石界面倾角较小时隧道围岩竖向变形规律差别较大,在土石界面倾角较大时其围岩竖向变形规律相近;随着土石界面倾角的增大,当隧道由黄土地层向破碎岩体掘进时,其拱顶变形量减小;当隧道由破碎岩体向黄土地层掘进时,隧道拱顶变形量随着掌子面的远离先增大后减小规律减弱并消失。

The complex geological conditions at the junction of different geological media bring great difficulties to the excavation construction of tunnel engineering.The soil-rock boundary stratum is a typical representative of this geological situation.In response to tunnel excavation problems under that geological condition,based on a shallow buried highway tunnel,the numerical simulation of tunnel excavation response under different digging directions and different earth-rock interface dip angles is carried out.The characteristics of tunnel excavation response under different tunneling directions are compared.The influence of dip angle of soil-rock interface on tunnel excavation reaction is analyzed.The results show:Under different tunneling directions,the vertical deformation law of tunnel surrounding rock is different when the dip angle of soil-rock interface is small,and it is similar when the dip angle of soil-rock interface is large;With the increase of the dip angle of the soil-rock interface,when the tunnel is excavated from the loess layer to the fractured rock mass,the deformation of the dome is reduced.When the tunnel is driven from the fractured rock mass to the loess layer,the deformation law of the tunnel dome weakens and disappears,which first increase and then decrease as the working face moves away.