Liquefaction susceptibility analysis based on SPT and microtremor

摘要

This paper outlines the liquefaction susceptibility analysis performed at residential building that suffered a ground failure after 7.8 Mw Gorkha (Nepal) earthquake. Five boreholes were drilled with depth varying from 10 m to 40 m where Standard Penetration Tests (SPT) have been performed. Liquefaction susceptibility in each borehole has been analysed using deterministic approach and probabilistic approach for Peak Ground Acceleration (PGA) of 0.3g and moment magnitude of 7.8 Mw. The results of analysis show that liquefaction susceptibility is comparatively higher at borehole location BH05 at a depth range of 3 m to 4.5 m where silty clay was found with lower plasticity index, higher fine contents and having higher water table. Ground vulnerability index (Kg) values were calculated using Horizonal-to-Vertical fourier spectral ratio (HVSR) technique through microtremor survey to compare the results. The results show that microtremor based liquefaction susceptibility analysis can also be a good alternative indicator to find liquefaction susceptibility.