RAPID LOAD TESTING OF STONE COLUMNS TO AID DESIGN OF FOUNDATIONS ON IMPROVED GROUND

Building Codes and best practice require load testing of embedded structural foundation elements to validate design and construction execution quality. This requirement is particularly challenging when associated with ground improvement schemes relying on granular reinforcing/stone columns. Stone columns present an economic solution for improving the bearing capacity of shallow foundations on soft soils. A novel impulse load test was developed and used to quantify the load-displacement response of shallow foundations supported on stone columns at a clay site. The device is referred to as the Rapid Plate Load Tester (RPLT) and is a modified version of the Axial Compressive Force Pulse test for deep foundations. In this paper, the comprehensive site investigation, stone columns construction, load testing procedure, and data analysis are described. Static and dynamic field tests were performed to target loads of 2000 kN and equivalent bearing pressures of 500kPa. The results obtained from the RPLT tests were used to derive equivalent static load settlement curves for footings on both the natural clay ground and improved ground and compared with the results obtained from the full-scale static load tests.