Correlation of Pressuremeter Test Results with SPT NValues and Liquidity Index for Cohesive Soil of Normal Calcutta Deposit

Economical geotechnical design requires proper sub-soil characterization by means of its consistency, compressibility and strength. In this respect, conventional borehole (BH) accompanied by standard penetration test (SPT) and laboratory tests is commonly conducted in the geotechnical investigation. Pressuremeter test (PMT) may be used to characterize the sub-soil profile by two parameters, i.e., limit pressure (PL) and pressuremeter modulus (EPMT). It is necessary to predict a standard range of these parameters of the sub-soil formation. In the present study, correlation between PL, EPMTwith standard penetration value (SPT N) and EPMT/PLwith the liquidity index (LI) for the cohesive (silty clay/clayey silt) sub-soil of Kolkata, India, are proposed. Further, a reference range of PL, EPMTand EPMT/PLis predicted for the same type of soil. Forty-eight numbers of PMT tests are carried out adjacent to the conventional boreholes, at three different sites, located in and around Kolkata city. The comparison of PLand EPMTwith SPT Nand EPMT/PLwith the liquidity index (LI) is made for each site. Finally, a typical range of PLand EPMTfor different SPT Nvalues along with the range of EPMT/PLfor different value of LI is established.