Hamid Alielahi - Assistant professor, Department of Civil Engineering, Zanjan Branch, Islamic Azad University, Zanjan, Iran
Arash Rostami - MS.c in Earthquake Engineering, Islamic Azad University, Tehran, Iran

Soil softening phenomenon may occur because of two main categories of land deformation caused by the extra pore water pressure and changes in site response due to softening soils susceptible to liquefaction. This article analyzes the role of strain energy and pore water pressure in changes of enlargement pattern of seismic response of susceptible to liquefaction lands, by applying a wide range of earthquakes on the basis of nonlinear method, total stress and effective stress in time zone. During the past years many different models in relation with pore water pressure model and liquefaction have been progressed. The accumulation levels between hysteresis loops at any moment represents the wasted strain energy and contains shear strain amplitude, number of cycles, and is combination of strain and stress effects; and offers an acceptable physical fact. For achieving the purpose, this study is the first to add a related parameters of pore water pressure (SLP) and cumulative strain energy (SSEP) result of dual integration to cover the duration of the effects of earthquake shakings, and thickness of the layer in which pore water pressure has been generated, are presented in three different ranges. So, in first step, liquefaction of Novada sand (with density of 40%) was assessed using test results of 1 centrifuge model in Velacs project using the one- dimensional finite software of site response CYCLICID, and thereby validating of numerical software has been done accurately. Then, using the acquired results, enlargement patterns of land responses in different ranges have been offered and evaluated. The results show that in soils susceptible to liquefaction, high levels of strain energy and pore water extra pressure generation would cause decrease in enlargement levels of seismic response of earth surface.

Strain energy ، Pore water extra pressure ، Enlargement pattern ، Site effects ، Domain ، Strong movemen ،