Comparative Study on the Coefficient of Radial Consolidation Determined from Various Methods

Vertical drains are often used to accelerate the pre-consolidation settlements in soft clay soils. The coefficient of radial consolidation (C_r) is one of the important parameters that governs the rate of settlement. Several researchers have proposed different methods to estimate the coefficient of radial consolidation. This paper attempts to compare the C_r value and ultimate settlement (S_f) by two empirical methods using data from an instrumented field test. The field data was obtained from the marine reclamation project for the extension of existing port at Mumbai, India. Prefabricated Vertical Drains (PVDs) along with preloading was successfully applied at the site to consolidate the soil. C_r values were calculated from the deformation data measured beneath an embankment through field instrumentations such as settlement plates. Many studies reveal that the laboratory test value deviates from the actual field value due to size effect and other factors hence, it is of utmost importance to determine more representative value of C_r from back analysis of field measurements. The degree of matching and the discrepancies in the values of C_r and S_f obtained from various available methods is described in the current paper.