Engineering Behavior of Dredged Soil with Precipitated Silica

In this study, it is proposed to improve the dredged soil extracted from Narayanapuram Lake of Chennai using precipitated silica. Dredged soil is a universally known soil waste produced while dredging of lakes, seas, rivers and dams. The dredged soils when accumulated in large quantities pose a serious threat for disposal and environment all around the world. Though in abundant, the strength parameter of dredged soil won’t agree with the foundation requirements. So there is a huge need for improving such soils. One of the commonly used high performances thickening agent in chemical industries is precipitated silica. It is formed by the reaction of an alkaline silicate solution with mineral acid. Dredged soil was collected, dried, pulverized and the basic index and engineering properties tests were carried out by varying the percentage of precipitated silica with respect to the weight of the dredged soil. Desirable results were obtained and the optimum percentage of precipitated silica was derived using the experimental investigations conducted in the laboratory. Detailed investigation of dredged soil carried out in the laboratory revealed that the addition of 4% of precipitated silica with loose dredged soil improved its shear strength by 42.85% and makes it dense.