摘要
研究表明,边坡中的地下水对坡体的稳定系数起着决定性的作用,然而在三峡库区滑坡的治理设计中,计算库水作用下坡体中的地下水位时,尚没有统一的方法,不同的单位根据以往的经验选用不同的方法,这些方法大都缺乏理论依据。为了完善库水下降情况下边坡的稳定性分析方法,根据包辛涅斯克(Boussinesq)非稳定渗流微分方程,通过拉普拉斯正变换和逆变换,得到了库水位下降时坡体内浸润线的简化计算公式,该公式考虑了渗透系数、下降速度、给水度、含水层厚度和下降高度的影响。以求得的浸润线为基础,用流网的流线与等势线垂直的性质来确定土条边界上的静水压力,证明了渗透力与土条中的水重和周边静水压力是一对平衡力,得到了条分法中渗透力的计算公式。算例分析表明,在库水下降过程中,存在一个对坡体稳定性最不利的水位,该水位在坡体总高度的下1/3～1/4位置。
It has been proved that the ground water plays a fateful role in the safety factor of slopes. However,in the stabilization design of the TGRZ slopes,the methods adopted for determining the ground water table and hydrodynamic forces during reservoir drawdown are mostly empirical and varied from one project to another. To improve the analysis methods of landslide stability under drawdown conditions,based on the Boussinesqs differential equation of unsteady-seepage,and Laplaces transform,a simplified formula is obtained of phreatic surface in landslide mass under drawdown conditions. The simplified formula takes into account the factors of hydraulic conductivity,velocity of drawdown,aquifer thickness and height of drawdown. According to the free surface in landslide mass,the boundary water pressure is defined utilizing the flow net property with orthogonal flow line and equipotent line. It is proved that the seepage force is in equilibrium with the water weight and the water pressure around the slice. The formula of seepage forces is established in slice methods. Finally the effect of above factors on landslide stability is discussed with examples. The result shows that there is a minimum safety factor when the reservoir level is at about 1/3～1/4 of the slope height.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2004年第18期3203-3210,共8页
Chinese Journal of Rock Mechanics and Engineering
关键词
岩土力学
地下水
浸润线
渗透力
稳定分析
rock and soil mechanics,drawdown,landslide,phreatic surface,seepage force,stability analysis
