DEEP SOIL EFFECT ON SITE AMPLIFICATION

Abstract

Presence of deep soil has a great effect on site amplification. Under strong ground motion the site having deep soil profile experiences severe shaking, which further leads to damage of the structure over it. Hence the study of behavior of deep soil and its influence on the response of site is very important. In this dissertation report, deep soil effects under strong ground motion are studied. The report contains a brief introduction of deep soil and its influence on site amplification under seismic activity. A study is presented in the report explaining the presence of deep soil in Mississipi embayment and amplification of this soil during strong ground motion. Also a study of Michoacan Earthquake and effect of deep soil causing severe damage in Mexico City located at 350 km away from the epicenter is also described. GROUND 1'ENETRATING RADAR is used to investigate the ground and to collect soil layering data. Effects of dielectric constant of material on the penetration depth have been studied. Calibration for dielectric constant is carried out of the DEQ ground. Using this information utility scan was performed on the entire site. MASW test was performed on same sites and experimental dispersion curves • are obtained after processing of field data. Shear wave velocity profiles have been extracted after the inversion of the experimental dispersion curve developed from the field tests. Using layering information from GPR testing, shear wave velocity profile with depth is formulated. Ground response analysis is performed on different site models using layering data from GPR and MASW. The site surface response is obtained using ground response analysis from GPR and MASW layering data and the differences in amplification are compared In first site, lesser amplification is found out from GPR layering data compared to MASW layering data, whereas in other site more amplification is noticed from GPR layering data compared to MASW layering data. The layering data from GPR is more reliable compared to MASW data. Use of GPR along with MASW provides the reliable profiles.