A SURVEY OF CONCRETE SLUMP EFFECTS ON THE COMPRESSIVE CAPACITY OF DRILLED SHAFTS (CASE STUDY: SORKHROOD SITE)

Using deep foundations is a solution in regions with surface soil having poor mechanical properties. Indeed this kind of foundation can bear horizontal, gravitational and tensile forces. In this regard, researchers study eective various parameters on pile behavior in the laboratory, such as the eect of pile dimensions, soil properties, methods of installation, types of loading, and some other eective parameters. The bearing capacity of single drilled shafts with the eects of various slumps on poor gradation sandy soil is investigated in this paper, in Sorkhrood. Experiments related to the bearing capacity of a pile using 15 pile samples with 150cm length and 12cm diameter have been undertaken. The concrete used in the piles is considered as 5 discrepant groups, with constant slump of 10, 12, 16, 20 and 24cm and a compressive strength of 210 kg/cm. A strong polymer pipe has been used as a casing, drilled step by step into the ground and then taken from the ground frequently. According to the experimental observations, increasing the amount of concrete slump used in the pile body has a great in uence on pile bearing capacity. It is shown that the bearing of compressive piles has been increased in the higher slumps. Increasing the amount of slump, due to the combination of the casing of the pile with the soil around the casing, changes some parameters of the soil, reducing the shaping. The amount of its in uence leads to the double dierence between the bearing capacity of the pile lled with the lowest slump and the pile lled with the highest slump. It is indicated that the method presented by Janbo & Bousen is an entirely conservative method, while the method presented by Mayerhouf and Bousen is closest to the results of the bearing experiments in calculating the nal bearing capacity. Finally, the bearing capacity of piles is investigated and compared with common methods.