Field tests on behavior of the surrounding soil during helical piles installation in silty clay

Helical piles can be classified as partial displacement piles in terms of moderate advancement rate. However, its installation effect on surrounding soil is unclear. This study presented four field tests on the installation of helical piles with various dimensions in silty clay. The radial earth pressure and excess pore water pressure were measured during the installation processes. The installation effect of helical pile embedded in silty clay was comprehensively discussed and evaluated from multiple dimensions of time and space, based on the cavity expansion method (CEM) and Randolph and Wroth’s elastic–plastic method verified by field data. The research reveals that as the length of the helical pile increases by 1.0 time, the maximum variations in radial earth pressure and pore water pressure by a remarkable 25.0 times and 7.8 times, respectively. Additionally, when the shaft diameter of the helical pile expands by 20