- Compacted aggregate trenches are a method of soil improvement that could be substituted for commonly used aggregate piers in certain geometrical arrangements of shallow foundations. However, this type of ground improvement has little research to support the understanding of their contribution to improved strength of an unimproved clay soil. This study uses numerical simulations to address the current shortcomings in our understanding of the impact of compacted aggregate trench ground improvement on the bearing capacity of shallow foundations. Numerical models have been constructed in commonly-used software, FLAC 7.0, to conduct a parametric study of 92 different compacted aggregate trench configurations to determine their improvement relative to 15 different unimproved clay soil simulations. Typical construction equipment has been considered to establish the magnitude of various construction parameters to inform the parametric study. In the unimproved cases, different undrained shear strengths and footing embedment depths have been considered. The aggregate trench-improved models evaluate different compacted aggregate trench lengths, widths, and placement beneath a 3 meter wide strip footing in the same varying clay strength and footing embedment depths. The study demonstrates that the most significant impact to soil improvement is the placement location of the aggregate trench beneath the strip footing. Additionally, the parameter of aggregate trench length is found to have a greater contribution to soil improvement compared to trench width.
Key Words: Aggregate, Construction, Geotechnical, Improvement, Numerical, Trench