Seismic Site Classification Using Boreholes and Shear Wave Velocity: Assessingthe Suitable Method for Shallow Engineering Rock Region

摘要

This study presents site classification using 30 m average concept and newlyproposed soil average by considering 30 sets of boreholes and shear wave velocitydata. Shear wave velocity (V_s) is measured by carrying out multichannel analysis ofsurface wave (MASW) survey close to the boreholes drilled up to standardpenetration test (SPT) N value of up to 100 for no penetration. The SPT N and Vsvalues have been used to calculate 30m equivalent N (N_(30)) and Vs (Vs~(30)) values.These sites are classified and compared according to National Earthquake HazardsReduction Program (NEHRP). Study shows that Vs based classifications are betterrepresentations for shallow overburden sites, compared to SPT. The amplificationfactors are estimated using Vs~(30) and empirical equations, and compared withamplification factor from site response studies. Further, applicability of SPT N valuesand average 30m values are investigated for shallow engineering bed rock sites.