中文摘要：

复杂基坑边坡具有明显的三维效应，目前计算方法尚不便准确计算其三维稳定性，不便于确定其空间失稳范围。在三维数值计算结果的基础上，选用Bezier双三次曲面对通过节点的位移等值面进行拟合，以位移等值面作为基坑边坡局部破坏面，据此计算出垂直破坏面的正应力和滑动方向的剪应力，提出新的点安全系数定义为该点抗剪强度与滑动方向上剪应力的比值，整体安全系数为等值面上点安全系数对面积的加权平均值。分析了某师范大学基坑边坡的稳定性，结果表明，点安全系数在剖面分布上呈中部小，内、外高的分布特征，小于1.06的区域从坡脚延伸至坡顶，揭示了滑动面的位置，最危险滑动面为15 mm的位移等值面。通过与刚体极限平衡法比较，验证了特定剖面上二者计算结果的一致性。

英文摘要：

Complex foundation pit has explicit three dimensional effect, and the three dimensional stability of the pit cannot beobtained exactly with present computational methods. The space failure range also cannot be defined easily. The Bezier bicubic curvedsurface is adopted to fit the displacement isosurface which passes the nodes; and it is assumed that the displacement isosurface is alocal failure surface of the pit slope. Then the normal stress vertical to failure surface and the shear stress along the slip direction arecalculated. A new point safety factor is defined as the ratio of shear strength at the point and shear stress along the slip direction; andthe whole safety factor is the weighted average value of the point safety factor according to the area. The stability of pit slope in anormal university is analyzed. The results show that point safety factor has the characteristics of small values in the middle and highervalues at two ends along the profile. The region with the values of point safety factor less than 1.06 extends from the bottom to the topof the slope, which indicates the location of slip surface. The dangerous slip surface is the displacement isosurface with values of! 5 mm. The consistency of computational results along the specified profile by the methods of rigid equilibrium method and pointsafety coefficient has also verified.