Slope stability assessment is extremely important in geotechnical engineering, as it prevents slope failures and the loss of lives. This paper utilizes the finite element lower bound limit analysis method to investigate and develop a set of 3D stability charts for fill slopes where frictional fill materials are placed on undrained clay with increasing shear strength with depth. Based on the stability charts, preliminary slope designs can be performed with convenience and ease, which is advantageous during the preliminary design stage when options and cost-saving solutions are more important than detailed design. Additionally, for comparison purposes, the results from twodimensional analyses are also presented and discussed. This study shows that the ratio of F3D/F2D is always larger than unity. Discussions on the factors affecting the failure mechanisms of this type of slope are also presented. In particular, a better understanding of such failure mechanisms allows engineers to better predict the footprints and consequences of the failures of such slopes.

边坡稳定性评估在岩土工程中极其重要，因为它可以防止边坡破坏和人员伤亡。本文利用有限元下限分析方法研究并开发了一组填方边坡的 3D 稳定性图，其中摩擦填方材料放置在不排水粘土上，抗剪强度随深度增加。基于稳定性图，可以方便、轻松地进行初步边坡设计，这在初步设计阶段是有利的，因为选择和节省成本的解决方案比详细设计更重要。此外，为了进行比较，还介绍并讨论了二维分析的结果。这项研究表明，F3D/F2D 的比率始终大于 1。并对影响此类边坡破坏机制的因素进行了讨论。特别是，更好地了解此类失效机制使工程师能够更好地预测此类斜坡失效的足迹和后果。