Effect of element size on the static finite element analysis of steep slopes

The accuracy of the computed stress distribution near the free surface of v ertical slopes was evaluated in this study as a function of the element siz e, including aspect ratio. To accomplish this objective, a parametric study was carried out comparing stresses computed using the finite element metho d (FEM) to those obtained from a physical model composed of photoelastic ma terial. The results of the study indicate a reasonable agreement between a gelatin model and the FEM model for shear stresses, and an overall good agr eement between the two models for the principal stresses. For stresses alon g the top of the slope, the height of the element tends to be more importan t than width or aspect ratio, at least for aspect ratios up to 4. In all ca ses, the greatest difference between the two models occurs in the vicinity of the slope. Specifically, if H is defined as the slope height, an element height of H/10 appears to be adequate for the study of stresses deep withi n the slope, such as for typical embankment analyses. However, for cases wh ere tensile stresses in the vicinity of the slope face which are critical, Such as for the stability analysis of steep slopes, element heights as smal l as H/32, or higher-order elements, are necessary. Copyright (C) 2001 John Wiley & Sons, Ltd.