Hi all,

I have one question regarding the movement of sliding block in FEM analysis.

Perhaps, most of you knew the famous paper of Griffths et al. (1999) where he applied FEM for slope stability analysis. In this paper, he carried out the tests for a homogeneous slope with and without foundation layer. Results gave similar safety factor but there is significant difference about the movement of the sliding block after the slope failure. Based on the meshed distortion in his paper, one could see that large displacement was observed for the slope with foundation layer and there is a toe failure in this case too.

The problem is that I recently applied mesh-free method to simulate slope collapse after failure. I tested the same problem and found different results regarding the movement of the sliding block. The sliding block in my test was larger for the case without foundation layer. I performed some further tests and found that the movement of the sliding block was significantly influence by the toe failure. This means that the sliding block will soon stop after failure if there is a toe failure. On the other hand, the sliding block will slide freely along the potential slip surface if there is no a toe failure.

These results are very different from FEM where sliding block can slide freely along the slip surface regardless of the toe failure. It is note that there is no update mesh in FEM.

Could someone help me to explain why this happens? Should FEM has any problems in this situation since the grid structure was completely distorted?

Thank you very much in advance!