中文摘要：

针对一座浅埋偏压隧道,采用FLAC3D对该隧道进口段进洞开挖进行动态施工三维数值模拟。基于围岩应力分布特征,仰坡坡面轴向和横向位移的变化特征,分析了偏压浅埋隧道洞口段开挖引起的仰坡变形规律。计算结果揭示：仰坡后缘下沉,前缘向洞心外有移动趋势;隧道开挖引起隧洞洞身附近岩体出现较大应力集中和变形现象,洞口段洞身以上仰坡坡面主要以竖向沉降为主,洞身两侧向洞内挤压。在此基础上提出了保证仰坡稳定和安全进洞的一些建议。

英文摘要：

Considering the case of shallow-embedded and partial pressure tunnel,the dynamic construction process of entrance excavation in the tunnel entry is numberically simulated with softwarw FLAC3D.In view of the stress properties in surrounding rock and the overland axis and lateral diplacement of side slope,this paper analyzes the overland deformation laws caused by entrance excavation of shallow-embedded and partial pressure tunnel.The calculated results show that the crown settlement offside of overland occered;the toe of the overland has a outwards displacement tendency;the biggish stress concentrations and deformation appeared in rock mass close to the tunnel because of the excavation,the side slope of overland above the tunnel entry has a mainly settlement displacement,and rock mass in the two sides of tunnel compressd towards tunnel center.Several advices to ensure the slope stability and entering tunnel safety has been suggested based on the analysis above.