EFFECT OF CLAY AND SILT CONTENT ON LIQUEFACTION POTENTIAL OF SAND

Abstract

Liquefaction of saturated sand has often been main cause of the catastrophic damage to structures resulting in loss of life and property. A foundation soil may not be all sand and may contain some clay or silt. Therefore in the present study the effect of clay and silt content in foundation sand has been investigated. Samples were prepared by mixing clay in Solani sand to have clay size particles of 2,4 and 6% and samples were also prepared by mixing silt in sand to have 5, 10 and 15% of silt size particles. These samples were tested on a horizontal shaking table subjected to steady state vibrations. It was found that by mixing the clay by 2% liquefaction potential of the soil has decreased but for 4% and 6% clay contents it is not so. No sand boils were observed in the case of clayey sand which may be due to role of plasticity of clay. For the case of silty sand at lower acceleration (0.10g) liquefaction potential was observed to be lower for lower percentage of silt and was higher for higher percentage of silt. But for higher acceleration level (0.19g and 0.28g) liquefaction potential was observed to be lower for all the samples tested. The time for pore pressure rise and dissipation increases as the percentage of finer particles increases.