Case study on damage of Banqiao School due to liquefaction following Wenchuan Ms 8.0 Earthquake

The liquefaction-induced damage of Banqiao School building following the 2008 Wenchuan Ms 8.0 Earthquake is typical,and the correlation between the ground fissures and the liquefaction is identified and mechanisms of the building damages as well as the characters of liquefied soils are investigated by field investigation and in-situ tests,such as multi-channels electric resistance test,spectral analysis of surface wave(SASW),dynamic penetration tests(DPT),borehole and trench,etc.The results show that:(1) the ground fissures are generated by the liquefaction rather than the secondary faults and ruptures;(2) Banqiao School building suffered more severe damages than its surrounding buildings from the liquefaction rather than inertia force of shaking during the Earthquake;(3) the subsurface liquefied soils are gravelly soils at the depth of 3.0-6.1m,which is different from the spouted fine sands;(4) the current knowledge is not true that the gravels are regarded as non-liquefiable soils,and a new procedure for liquefaction evaluation of gravelly soils is demanded.