Influence of valley geometry on stability of an earth dam

摘要

Influence of valley geometry on stability of an earth dam is assessed in terms of its static slope stability. Numerical model results for an earth dam sited in a trapezoidal valley are presented for two combinations of dam crest length and valley floor width. In one combination, the valley floor width is held constant and the slope of valley walls is varied; in the second combination, the dam crest length is held constant and the slope of valley walls is varied. The results for the two combinations are not the same. The results presented are from three-dimensional (3-D) and two-dimensional (2-D) continuum-mechanics-based numerical analyses and are in terms of factor of safety (FoS) and associated slip surface. Significant results include: (i) influence of valley geometry on FoS is minimal when valley floor width exceeds about five times the dam height; and (ii) ratio of 3-D to 2-D FoS can be in the range of 1.03 to 1.30 depending on the valley geometry. Practical implications of the results are included.