Bearing capacity of square footing resting on lime-sand soil

This study aims to evaluate the bearing capacity of shallow square footing resting on an artificially treated lime-sand soil layer, considering the influence of the treated layer thickness (H) and different dry unit weights of the soil layer beneath the treated layer. Additionally, the effect of lime content on the unconfined compressive strength (UCS) of lime-treated sand was also investigated. The data were obtained from loading tests carried out on a square steel plate model (89 mm length, 89 mm width, and 23 mm thick) placed on the top of an artificial lime-sand layer with H/B = 0.1, 0.3, 0.6, 1, where B is the width of the footing. The sand under the artificial layer was compacted with two dry unit weight values (14.4 and 15.8 kN/m³), thus, achieving the loose (33%) and dense (77%) states, respectively. Different percentages of lime (5, 7, 10, and 15%) were added to examine the strength of treated sand soil with lime. The results showed that the increased H/B ratio affected the stress-settlement curves and improved bearing capacity with the bearing capacity ratio (BCR) rising from 1 to 2 in loose state and from 1 to 1.9 in dense state. Small scale load tests of square footing resting on lima-sand treated layer on the top of sand with different dry unit weights revealed two failure modes. For H/B = 1 with the lowest dry unit weight, the treated layer punched through to the sand soil without visible fissures until reaching the bearing capacity of the underlaying sand. For lower H/B ratios (0.1, 0.3), the lime-treated soil layer fractured, forming cracks near the footing edge and central axis, whereas higher H/B ratios (0.6, 1) resulted in cracks primarily near the footing edge.