无厚度界面单元边坡浅基础极限承载力上限值的数值分析

采用研发的有限单元分析程序，并同时考虑以库仑摩擦界面为组成模式的多段式无厚度界面单元，藉以探讨边坡坡角与坡缘距离对边坡坡顶浅基础极限承载力的影响，并应用于不同几何破坏机制条件，计算边坡基础在凝聚性土体的最小荷载上限值，模拟土体间的滑动破坏趋势与渐进式破坏行为。研究分析内容包含：（1）浅基础位于半无限空间；（2）在不同边坡坡角条件下，浅基础位于坡顶边缘处；（3）在不同边坡坡角条件下，浅基础位于不同坡缘距离等。经由数值计算分析结果显示，坡缘距离值愈小或边坡坡角愈陡峭时，边坡浅基础极限承载力值则愈小。换言之，当浅基础位于坡顶边缘处且坡角为垂直开挖情况时，则导致浅基础极限承载力降低约50 %。

Numerical analysis of the upper bound limit analysis of shallow foundation on slope by using zero-thickness interface element approach

For research on the ultimate bearing capacity of shallow foundation on slope, it uses the finite element analysis with the multiple zero-thickness interface elements which considers the Coulomb’s failure criterion. The influence factors of ultimate bearing capacity, slope angle and distance from the slope margin are particularly studied. The minimum upper bound of bearing capacity and the behavior of progressive failure are also investigated in this research. The ultimate bearing capacity calculated in this study is taken account that shallow foundation is seated on (1) the semi-infinities ground, (2) the slope margin and (3) the distance from the slope margin. The results obtained shown that the ultimate bearing capacity of shallow foundation decreases as the values of influence factors decreases. In other words, while the shallow foundation seated on the slope margin during the vertical slope excavation, the value calculated of ultimate bearing capacity decreases about 50 % less than that obtained by the case of semi-infinities ground.