A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Geotechnical & Geoenvironmental Engineering, School of Engineering and Technology

Thesis (M. Eng.) - Asian Institute of Technology, 2011

The correlations between geotechnical and geophysical parameters, in particular correlations between elastic constants calculated from pressuremeter and downhole seismic test were evaluated for a site in HCMC, Vietnam. The geotechnical data collected from study site included field test and laboratory test data. The field test data consist of pressuremeter test (PMT) data, downhole seismic test (DST) data and SPT value (N), the laboratory test data consist of grain size, water content, liquid limit, plastic limit, void ratio. Soil characterization at the study site was done based on laboratory test data. The results of analysis of DST data (VS and VP) were used to calculate elastic constants such as Young{u2019}s modulus (ESeis), Shear modulus (G), Bulk modulus (K), Poisson{u2019}s ratio, Lame{u2019}s constant (L). The VS, ESeis and G values were correlated with corrected N values. Similarly, Values of Young{u2019}s modulus (EPMT) and shear strength (S) obtained from analysis of PMT data were also correlated with corrected N values. Efforts have been spent to analyze pressuremeter test data, especially to predict the limit pressure (PL), based on which the soil strength can be calculated as S = 0.67PL*0.75. For the medium dense sand layer, it was found out that Young{u2019}s modulus (EPMT) calculated from pressuremeter test is about 4.3 times of Young{u2019}s modulus (ESeis) calculated from downhole seismic test as presented by equation EPMT = 0.23ESeis