Abstract
Seismic dilatometer test (SDMT) was conducted in the Salt Lake campus of Jadavpur University, Kolkata using Marchetti’s SDMT equipment. Another location in Kolkata was chosen where alluvial deposits were encountered for performing liquefaction analysis by SPT method only. Using the usual correlations as mentioned in the report of the ISSMGE TC 16 on ground property characterization from in-situ testing (2001), oedometer modulus, undrained shear strength, friction angle and shear wave velocity profile were found out. In the same location, standard penetration test (SPT) was also carried out. Based on the field SPT values and visual soil classification, a sub-soil profile was delineated. Engineering properties of the various layers were determined from standard correlations available in the literature. It was observed that both the sub-soil profiles obtained from these two tests were more or less similar. In the present investigation, an attempt has been made to compare the results of these two methods viz., seismic dilatometer test (SDMT) and standard penetration test (SPT). Based on the small strain shear modulus from DMT as well as shear wave velocity profile from SDMT tests, an effort has also been made to determine the liquefaction potential and settlement of post earthquake condition of the sand layers using standard charts given by Ishihara and Yoshimine (1992). Besides, using the correlation between (N1)60 and volumetric strain (εv) as reported by Tokimatsu and Seed (1987), the same were obtained for SPT tests. Subsequently, comparison is made between results of these two methods. Finally, recommendations are made regarding the suitability of these two methods with particular reference to liquefaction potential and post earthquake settlements.
