Lateral bearing characteristics of modified suction caisson embedded in layered soil

Model tests and numerical simulations were conducted to investigate the lateral bearing characteristics of a modified suction caisson (MSC) in layered soil. The impacts of the loading eccentricity and the soil layer distribution on the lateral bearing capacity, rotation point position variation and soil deformation behavior were studied. Results indicate The MSC lateral bearing capacity in sand-over-clay is greater than that in clay-over-sand. In both sand-over-clay and clay-over-sand, the MSC bearing capacities were all found to increase with increasing the sand layer thickness. During lateral loading, the MSC rotation point continuously move downward and finally reaches the stable position in the limit state. The final embedded depths of the rotation position under various soil types are as follows: clay-over-sand is the deepest, sand is next, sand-over-clay is the next, and clay is the shallowest. In addition, the three-dimensional soil deformation zones around the MSC were obtained. The three-dimensional elliptic shaped soil deformation strain wedge boundary surface at the front side of the MSC along the loading direction extends linearly from MSC internal compartment outer wall (with the embedded depth where the rotation point is located) diagonally upward to the topsoil surface. The boundary of the deformed topsoil surface at the front side of the MSC along the loading direction can be fitted as an elliptic function. Based on the test and numerical results, solutions calculating the lateral bearing capacity of the MSC in layered soil were proposed using the limit equilibrium method and earth pressure theory. Results show that the proposed solution can well predict the lateral bearing capacities for the MSC and the TSC in sand, clay and layered soil.