Case studies and site investigations paper
Chandran, D, Anbazhagan, P, Quan, Y, Abdul Kadar Prabhu, H 2014, 'Integrated site investigation of shallow bedrock sites for seismic site response study', in ST Smith (ed.), 23rd Australasian Conference on the Mechanics of Structures and Materials (ACMSM23), vol. II, Byron Bay, NSW, 9-12 December, Southern Cross University, Lismore, NSW, pp. 1249-1254. ISBN: 9780994152008.
Study of seismic hazard and site response are essential and has become mandatory for the design of important structures. Subsurface investigation is an important step, from where input parameters for site response studies like shear wave velocity (Vs), density, thickness and damping characteristics etc are obtained. Most of the site response studies at shallow bedrock site are usually carried out by using Standard penetration test (SPT) N values and Vs from Multichannel Analysis of Surface Waves (MASW) with assumption that soil layers are horizontal, uniform and homogeneous. These assumptions are not completely true in shallow bedrock region due to heterogeneous soil deposits. The objective of this study is to generate subsurface profiles at shallow bedrock region using integrated site investigation testing. In this study drilling of borehole with SPT N value measurement, seismic testing of MASW and Electrical Resistivity Tomography (ERT) has been carried out at selected locations in Hampi, Karnataka, India. SPT gives soil type and density, MASW gives shear wave velocity and resistivity testing gives layer thickness. Integrated subsurface profiles are generated and are used to understand variation of subsurface layers in shallow bedrock sites and validate 1-D site response study assumptions. These subsurface profiles may be further used to understand difference of 1-D and 2-D site response.