Published Paper Details:

This study had made to reinforce the problematic black cotton soil and to avoid the settlement of the foundation, by installing Micro-Piles (M-P) individually and in group. In the group piles, the three pile group and four piles group is adopted in this study. The three pile group is installed in triangular pattern, whereas the four pile groups installed in square pattern at different length and different spacing, also the group efficiency is determined for both patterns and is compared with each other. The model tests were performed with the use of mild steel model test tank of dimension 350mm in length, 350mm in width, 350mm in depth and the model footing of the size 140mm x 140mm of 6mm thick. The analysis was carried out for individual and group piles of respective pattern which are installed in the black cotton soil with different lengths i.e. 30%, 50% and 70% of length and spacing of 2D, 3D and 4D respectively, where D=dia of micro-pile. The vertical load is applied to experimental setup and the ultimate bearing resistance is recorded with respect to 30mm settlement. It is examined that, the ultimate loads bearing resistance of the M-P in Black Cotton Soil rises with increase in length and spacing between the piles. Due to upraise in the load holding capacity, inversely the foundation settlement also decreases, it also observed that the load taken by the piles increases with increase in their numbers. The maximum load of 14.6 KN and 18.8KN is observed in three and four numbers of piles and 7.8 and 13.5KN is the least loads observed in three and square group piles respectively. When it comes to the Group efficiency (GE), it is found that the GE decrease with increase in the length, but the GE elevates with increase in distance between the piles, the GE observed in different patterns of triangular and square pattern of group piles. It is observed that the GE has a peak value of 79.24% in Square pattern at 30% of length and spacing of 4D, minimum value of GE is found to be 42.59% in triangular pattern at 70% length i.e. 245mm length at spacing of 2D.