Use of stone columns in soft marine clays

In this investigation, the use of stone columns to stabilize soft marine clays has been studied by conducting laboratory load tests. The load tests are carried out on three diameters of stone columns with different lengths, placed in clay bed prepared at different consistencies. The results indicate that the stone columns transfer the toads to the surrounding soil by bulging action, which mobilizes passive resistance. The bulging of the columns is found to be more pronounced in soft to medium stiff clays. The coefficient of passive resistance is found to be decreasing with increasing length of the column. It is observed that the relative rate of increase in the ultimate load carrying capacity of the stone columns becomes asymptotic with the increase in the column length. This indicate that the length of stone column will be ineffective beyond a certain value and it can be optimized. For the soil conditions used, the optimum length of stone column is found to be between 5 and 8 times the diameter of the stone column.