Proposed strength and stiffness parameters for normally consolidated and overconsolidated Dhaka clay

Abstract

The undrained shear characteristics of reconstituted normally consolidated and overconsolidated samples of Dhaka clay are discussed. The disturbances on the soil structure result from sample penetration that reduces the values of undrained shear strength (su) and initial tangent modulus (Ei), initial effective stress (σ´i) and pore pressure (u) but increases axial strain at peak deviator stress (εp). The changes in soil parameters between the “in situ” and “tube” samples are very much dependent on the geometry of the samplers used to retrieve “tube” samples. The values of su, Ei and σ´i of samples reduced while the values of εp increased with increasing area ratio (or decreasing external diameter to thickness ratio) and increasing outside edge angle (OCA) of the samplers. For optimum and economic foundation design, the correction for undrained strength and stiffness parameters are proposed due to the soil sampling disturbance