Liquefaction survey and case analysis in Wenchuan earthquake

Total 163 survey points distributed in 104 liquefied and non-liquefied sites were selected in the Wenchuan earthquake liquefaction database, where 50 survey points were from intensity VI region. Borehole data show that pure sandy layers could hardly be identified in Wenchuan earthquake affected areas, instead gravel soil layers mingled with sand silty or pebble prevalently exist. Songbai village which suffered severe liquefaction was chosen for case study in this paper. Through MASW and high density electrical method testing, three soil layers can be distinguished from the testing cross section. The discontinuity of resistivity of the first layer by the high density electrical method indicates the location of sand ejection. The grain size distribution curves of sand ejecta were different from drilling soil samples, which explanation need further investigation.