Failure surfaces are very effective in active lateral earth thrusts acting on cantilever retaining walls. The intersection of failure surface and cantilever retaining wall should be taken into account for determination of active earth thrust. Calculations of lateral earth thrusts vary for two different cases, short heel or long heel, based on the intersection of cantilever wall and failure surface. However, the common methods are devoted to a particular case (long heel or short heel). This study intended to suggest a new lateral earth thrust method that is applicable to cantilever walls with a short heel or long heel using the limit-equilibrium approach. For this purpose, an earth thrust-maximization algorithm was prepared and coded by using Matlab Environment to determine active earth thrust coefficients and failure surface inclination angles occurring behind a cantilever wall in an active case. Also, the failure surfaces occurring behind model cantilever walls and the failure cases were examined experimentally by using particle image velocimetry (PIV) analysis. Consequently, long-heel and short-heel cases and the effective parameters on the cases were investigated analytically and experimentally. (C) 2019 American Society of Civil Engineers.