A practical procedure for searching critical slip surfaces of slopes based on the strength reduction technique

Once an earth slope is led to the limit equilibrium state by means of the finite element–strength reduction technique, a plastic zone will go through the slope from the toe to the top. Based on the observation that the critical slip surface will be within the plastic zone and be composed of the points at which the equivalent plastic strain arrives at the maximum in the vertical direction. First, some vertical lines are arranged along the horizontal direction. Then, along each of the vertical lines the point with the maximum equivalent plastic strain is found out. All such points take on a shape of wave and form the functional data. Finally, the functional data are smoothed by the least squares and the position of the critical slip surface is determined. The proposed procedure is verified through comparison with other procedures.