PERMEABILITY AND CONSOLIDATION BEHAVIOR OF COMPOSITE GROUND REINFORCED WITH SAND COLUMNS

In this paper, the behavior of the composite ground reinforced with sand columns with and without smear effect installed in 200mm long and 100mm diameter cylindrical clay specimens was investigated using conventional triaxial consolidation tests under different confining pressures ranging from 50kPa to 575kPa. Change in volume of the specimen was measured using automatic volume change apparatus. This typically required a consolidation time of about 100minutes compared to more than 6-7days required to consolidate the specimen without the sand columns. However, specimens prepared with smear effect took slightly more time to consolidate thereby lending further confidence to the method used to create the smear zone. The test results showed that the dissipation of excess pore water pressure occur faster in the radial direction due to the greater coefficient of soil permeability in the horizontal direction and the reduced drainage path.