Dynamic Response of Stabilized Soft Clay Under Cyclic Loading at Low Shear Strain Level

Abstract

Grand construction projects all over Egypt require large infrastructure projects. In Northern Egypt where large buildings are needed for new developments, large areas of soft soils are abundant. These buildings transfer heavy static and dynamic loads to soil. Soft clays can be stabilized to carry these loads with minimum settlements and high shear strength. This research focuses on improving the static and dynamic properties of soft clay using chemical stabilization by cement or lime. undisturbed samples were collected from Belkas, Dakahleia – Egypt. The engineering properties were determined and classified as soft silty clay (CH). Low proportions of added cement or lime between 4 and 8% by weight were mixed with the natural samples, The effect on the strength and dynamic properties of reconstituted samples were investigated. Three series of a free-fixed type of resonant column tests were conducted in torsional mode on natural soft silty clay, stabilized soft silty clay with cement, and stabilized soft silty clay stabilized with lime. The influence of confining pressure and stabilizer amount on dynamic shear modulus (Gmax) and material damping (Dmin) for natural and treated samples were studied. The threshold shear strain γth for each treatment type is investigated at small-to-medium shear strain amplitude levels to investigate the effect of torsional shearing on material softening behavior and normalized shear modulus (G/Gmax) degradation of treated soil. The results are presented and discussed displaying percentages stabilizers that led to significant improvement in the soil stiffness and shear modulus using cement or lime as the stabilizers, The damping ratio, (Dmin) decreased by increasing stabilizers dosage.