Assessment of Collapse Potential of Lumped Soil in Alluvial Deposit by Double Consolidation Tests

Alluvial soils transported by water are widely distributed in the arid and semi-arid regions of the world. Due to the increasing population in these regions, quantifying the collapse phenomenon in alluvial soil is essential for safe foundation design. This paper illustrates the assessment of the collapse potential of Ganga basin alluvial sand deposits to quantify the amount of soil settlement. A series of double consolidation tests have been conducted on the different percentages of sand and collapsible lumps mixture to study the variation of collapse behavior. The collapse potential increased linearly with the increase in collapsible lumps percentages in the soil mixture. The collapse potential had been estimated as 19.58%, 17.01%, and 12.22% in the case of alluvial soil containing 90%, 70%, and 30% collapsible lumps, respectively. The collapse potential of the alluvial soil with 100% collapsible lumps is almost doubled compared to soil containing 50% collapsible lumps and 50% sand in the mixture. The results of this study also provided insight into the volume change behavior of the soil mixture in saturated and unsaturated conditions. These experimental results and proposed guidelines will help to improve the design guidelines of foundations resting on collapsible lumped soil deposits in the Ganga basin and similar quaternary alluvial deposits.