The soil wedge is changing in shape and depth as the applied load is increased. At the top, the wedge fans out at the mobilized friction angle while it is some h in depth and the front face angle is ts at 45 plus the mobilized friction angle divided by two from the vertical, i.e. the mobilized passive wedge. If you contact Mohamed Ashour, he may provide you a version of the Strain Wedge program that provides this info. His email is [email protected].