Distribution and dissipation laws of excess pore water pressure based on pile-soil interface during pile-sinking in saturated clay

Abstract

PHC pipe pile cooperated with jacked method is widely used in recent years. The excess pore water pressure of pile-soil interface caused during jacked PHC pipe driving would produce important effect on jacked pile construction and bearing characteristics. Two full scale jacked-in piles are penetrated into the clayey soil and studied by monitoring the law of generation and dissipation of excess pore water pressure. The law of excess pore water pressure with penetration depth and time is also analyzed. From this test results, excess pore water pressure of the pile-soil interface increases to the peak and then begins to decrease, but it remains large. The excess pore water pressure of S1 test pile pile-soil interface decreases from 201.4 kPa to 86.3 kPa, and decreases from 374.1 kPa to 114.3 kPa for S2 test pile. The excess pore water pressure of pile-soil interface rises first at the initial stage of consolidation, and it dissipates when the hydraulic gradient between pile-soil interface and soil around the pile disappears. The dissipation degree of excess pore water pressure reaches from 75% to 85%. The proposed solution provides certain engineering significance for jacked pile construction and bearing capacity design in the clayey foundation.