Experimental Study on Pond Ash Reinforced with Stone Column of Varying Length and Area Ratio

Effective management of pond ash disposal is crucial in minimizing land wastage for coal-dependent countries like India, and one way is to improve its bearing strength by using Stone Column (SC) as reinforcement. The stress–strain behavior of pond ash is investigated in this work through various laboratory tests, i.e., the effects of varying length-to-area ratios of SC reinforcement, saturation, and compactive effort. The varying area ratios (A_r) of 10%, 20%, 30%, 40%, and 60% and length ratio (L_r) of 0.25, 0.5, 0.75 and 1.00 were adopted for this study. The study involved assessing the suitability of SC reinforcement for enhancing the strength of pond ash deposits. The present study carried out through two test series. The first test series assessed the index and engineering properties of pond ash, including compaction characteristics and shear strength parameters, using UCS, triaxial shear test, and footing load tests, along with index properties tests of the stone aggregate used to prepare SCs. The second test series focused on the evaluation of the load settlement behaviors of reinforced pond ash samples by UCS, triaxial, and footing load tests. The efficacy of SC reinforcement in improving the load bearing capacity (BC) of pond ash depends on parameters such as compaction energy, confining pressure, L_r, and A_r. However, it has been observed that when the SC confining pressure is inadequate, an increase in L_r and A_r is not effective in improving the load BC. In contrast, in a footing load test, it is noticed that the BC improved with an increase in the L_r up to 0.75 L_r; beyond this there is no significant improvement in the BC as the L_r is further increased. Therefore, when considering the efficient use of materials, 0.75 L_r is considered the optimal L_r for A_r.