路堑节理边坡开挖稳定性及影响因素分析

Analysis of Stability and Influencing Factors for the Excavation of a Jointed Rock Cutting Slope in a Road

以某公路节理岩质边坡为工程背景,首先利用FLAC3D建立该边坡的数值分析模型,计算得到5台阶开挖的安全系数分别为2.62、2.39、1.61、1.06、0.67,并确定其破坏模式为双滑块平面剪切破坏;然后针对边坡的破坏模式建立理论计算模型,分别改变节理的倾角和力学参数(c,),分析它们对稳定性的影响。结果表明:变化下滑块节理面的倾角时,安全系数先变小,而后逐渐增大;变化上滑块节理面的倾角时,安全系数逐渐增大;当c1、c2取值较小时,两者的变化对于安全系数的影响基本相同,但随着取值的增大,c2的影响效果逐渐大于c1。

A jointed rock slope cut in a road construction is chosen as the project background.Firstly,the numerical model of slope is established by using FLAC^3D.The computation results show that the safety factors of slope in five steps of excavation are 2.62,2.39,1.61,1.06 and 0.67,respectively,and the failure mode is of the type of bi-block slide collapse.Secondly,based on the failure mode,theoretical models are established for slope stability analysis.By changing dip angle and mechanical parameters（c and ） of joint planes,the influences of these parameters on the stability of slope are obtained,which show that：（1） the safety factor decreases firstly,then increases with the increase of the dip angle of the joint plane of the bottom slip block;（2） the safety factor increases gradually with the increase of dip angle of the joint plane of the upper slip block;（3） when the values of c1 and c2 are small,their influences on the stability of slope are approximately the same;but when they increase,the effect of c2 is larger than that of c1.