Characteristics of the permanent deformation and surface rupture caused by fault dislocation in 512 Wenchuan earthquake are analyzed in this paper. On the basis of the data from surveying reports and engineering geological reports of some observation station, three kinds of overlying soil model are established and analyzed, the physical parameters coming from clay and sand: thickness 30m and 50m model of the clay, thickness 30m model of the sand and thickness 50m model of the clay containing sand interlayer. Results show: The thickness of the overlying soil is same, but fault dislocation changed, the permanent deformation scale of overlying soil with velocity of shear wave from 250m/s to 500m/s is almost same, but the surface rupture zone is different: shear wave velocity of the soil is low, surface rupture zone becme wide. With thickness of the soil increassing, the rupture zone become wide too. Influence of sand interlayer is small. Considering the setback distance determination, the geometric and kinetic characteristics of faults, regional seismic activity, material properties and thickness of the overlying soil are key factors.
Probability analysis of setback distance based on structural damage near earthquake-fault-rupture
