黄土隧道基底区域围岩应力分布规律研究

为研究黄土隧道基底区域围岩压力的分布规律,采用数值方法建立三维有限元模型,用围岩应力等效围岩压力,分别考虑隧道不同施工方法、不同埋深的影响,从而得出隧道基底区域围岩压力在上述影响因素下的变化规律。分析可得台阶法基底围岩竖向应力值比其他施工方法小,CD法和CRD法在基底中线区域竖向应力值较大;在所研究的埋深范围内随隧道埋深的增加,其基底竖向应力值随之增大且埋深每增加10 m竖向应力增大系数在1.2~1.4等结论,为基底处理方案提供参考。

Research on Distribution Pattern of Surrounding Rock Stresses in Foundation Base Zone of Loess Tunnel

To ascertain the distribution pattern of surrounding rock pressure in foundation base zone of loess tunnel,a three-dimensional finite element model was built with numerical method in this paper. Afterwards,the surrounding rock stress was regarded as the equivalent of surrounding rock pressure,and different tunnel construction methods and different buried depths were taken into account respectively. Therefore the distribution pattern of the surrounding rock pressure in the foundation base zone of the loess tunnel was able to be acquired. Finally,some conclusions were drawn as below:( a) the vertical surrounding rock stress obtained by bench cut method is smaller than other construction methods in the foundation base zone of the tunnel,while the vertical stresses obtained by CD method and CRD method are larger along the centerline of the foundation base;( b) within the range of buried depths studied,the vertical stress in the foundation base zone will increase with the increase of the buried depth of the tunnel,and every increase of 10m in buried depth is associated with a magnification coefficient of about 1. 2 to 1. 4. These useful conclusions can serve as reference for treatment scheme of foundation base.