Torsional Shear and Resonant Column Tests on Cement Treated Marine Clay

Abstract

Cement treatment is one of the widely used ground improvement methods to enhance the strength and compressibility characteristics of soft marine clay deposits. This paper aims to compare the shear modulus and damping ratio obtained from torsional shear tests and resonant column tests for cement treated clays depending on the associated shear strain. It also examines the effects of cement content (0–10 % cc), confining pressure (100–300 kPa) and loading frequency (0.1, 1 Hz level) on secant shear modulus, damping ratio and normalized shear modulus reduction. The results reveal that the secant shear modulus calculated from torsional shear test is lower than the resonant column test. The variation in damping ratio calculated from both the tests has been found negligible for untreated clays. But clays treated with higher amount of cement content (10 %) show considerable variations in the medium strain range. Moreover, a few cyclic triaxial tests were conducted at the high strain (>0.1 %) to understand the connectivity between the different test results over the wide range of shear strain (0.001–1 %).