Experimental Investigation of Strip Footings on Weak Clay with a Granular Trench

Abstract

The necessity for moderate improvements in the stress-strain behavior of soft soil is common in geotechnical engineering. One effective method for stabilizing such soil involves the installation of a granular trench. This experimental study examines the performance of strip footings supported by granular trenches in soft soil, focusing on the effects of trench size, shape, and the friction angle of the trench material on bearing capacity and settlement. Results indicate that a significant enhancement in bearing capacity, up to four times, and a settlement reduction of approximately 54% were achieved when the trench depth and width were 4 and 2.5 times the footing width, respectively. Beyond these dimensions, improvements in load-bearing capacity and reductions in settlement became negligible. It was also observed that the greatest settlement reduction occurred when trench sides were inclined outward by 30o from the vertical, whereas the maximum bearing capacity improvement was noted with vertical trench sides. The friction angle of the trench material had a substantial impact on settlement and a moderate effect on bearing capacity. This investigation provides valuable insights for optimizing granular trench design to enhance the performance of strip footings on weak clay.