A few of the presented soil behavior models are capable of predicting the triggering and post liquefaction and also shear band mechanism through the soil media. The assessment of earth-dam body behavior as a soil structure made of cohesive soil in core and non-cohesive soil as the core supports, including water interaction at upstream through earthquake upon a multi-line constitutive equations is the aim of this paper. A multi-plane mechanism-based approach is successfully employed for assigning post-liquefaction displacement of earth-dam structures. This approach is derived from total stress procedures with two major advantages: 1) the triggering and post liquefaction response have been multi-lined into one analysis, and 2) the modeling of post liquefaction behavior is greatly improved. Analyses are performed in the time domain, allowing the imposed earthquake motion to affect both the triggering and post-liquefaction deformations. This Multi-plane based framework is employed to sum up the strength effects on integrated sampling planes and the resultant of this simulated multi-lined behavior is implemented at each finite element Gauss point. This multi-plane based model is also capable of predicting the effects of both induced and inherent anisotropy plus the rotation of principal stress/strain axes through the plastic behavior of both cohesive and non-cohesive soils. The approach is presented through the simulated of the case history as the response of the lower San Fernando dam to the 1971 San Fernando earthquake. The magnitude and pattern of the predicted displacements are shown to be in good agreement with the measured values.