Performance Assessment of Soft Soil Ground Reinforced with T-Shaped Piles Using Model Tests

Laboratory model tests were carried out to simulate the soft soil ground treatment with T-shaped deep cement mixing(TCM) piles in Jiangsu Province, China. The model test employed T-shaped gypsum piles to simulate TCM piles, and the performance of T-shaped piles in reinforcing soft soil grounds with varying water contents was investigated. The test results reveal that increased water content in soft soils leads to a significant increase in ground deformation, including surface settlement, ground uplift, and horizontal displacement. Compared to unreinforced ground, the ground reinforced with T-shaped piles exhibits substantial reductions in both settlement and horizontal displacement. In terms of bearing capacity, the pile-soil composite ground performs significantly better than the unreinforced ground, with the improvement becoming more pronounced as water content increases. Additionally, the soil water content significantly influenced forces on T-shaped piles. As water content rose, both the bearing capacity and cohesion of the soft soil decreased, resulting in more load transferred to the pile head. This directly increases the pile-soil stress ratio in soft soils with high water content, thus elevating the risk of pile failure. Moreover, most fractures occur at the variable section of the T-shaped pile due to the stress concentration at this abrupt geometric change.