Geotechnical capacities of large-diameter cylindric foundations in clay under general loadings

The large-diameter cylindric (LDC) foundation is the recently-emerging solution to support the bridge, wharf and storm surge barrier etc. used in the waterway, port and coastal engineering. Although it can be thought as a shallow foundation similar to bucket foundation without top lid, geotechnical capacities could be significantly different. It is because the absence of top lid potentially results in the change in mechanism of force transfer, thereby the change in failure mechanism. Therefore, this paper reports a comparative study of capacities for LDC and conventional circular skirted foundations in clay under general loadings. Both ultimate uniaxial and combined loadings capacities underlying the corresponding failure mechanisms are systematically investigated, with the effects of foundation embedment, foundation-soil interface and soil strength heterogeneity explicitly considered. Based on these, a suit of closed-form expressions is proposed to estimate the bearing performance of LDC foundations in clay under general loadings. Differences of LDC and conventional circular skirted foundations in bearing performances are compared, with the influence of absence of top lid on capacities discussed.