Groundwater effect factors for the load-carrying behavior of footings from hydraulic chamber load tests

The presence of groundwater level (GWL) causes changes in stiffness and strength of soil, affecting the bearing capacity and settlement of shallow foundations. In the present study, the load-carrying capacity and settlement of footings in sands under various GWL conditions were investigated. For this purpose, a series of model footing load tests and cone penetration tests (CPTs) were conducted using the hydraulically controlled chamber system. Different GWL and soil conditions were considered in the tests. The load-carrying capacity of footings became lower with increasing GWL, which was most significant within the depth of GWL (d_w) equal to footing width (1.0B). Larger reductions in the bearing capacity with GWL were observed for looser soils with lower relative density. Based on the test results, design equations and correlation parameters for the GWL effects on the bearing capacity and settlement were proposed as a function of GWL, applied load, and relative density. It was confirmed that the existing CPT-based correlations to footing bearing capacity are valid and applicable for soils with GWL.