THE VARIATION LAW OF NEGATIVE SKIN FRICTION OF PILE DURING SECONDARY-CONSOLIDATION OF SOFT SOIL

This paper designs single pile model box test in soft clay to simulate the pile settlement of progressive loading. It measures the change of the excess pore water pressure, surface settlement and pile axial force measurement. The influence of the lateral mode resistance of the pile foundation and the change of the position of the neutral point are analyzed when the soft clay is in the stage of secondary consolidation. The research shows that the settlement caused by the soil in the secondary consolidation stage has a certain effect on the negative skin frictional resistance. Along the pile, the negative skin frictional resistance is first increased and then decreased. When the load level is up to a certain degree, the neutral point can move up as the consolidation time of the soil around the pile increases, the settlement caused during the secondary consolidation stage is related to the load level applied to the soil around the pile. As the load level of the pile increases, the proportion of the total settlement of the secondary-consolidation stage decreases gradually. The creep effect of the pile is gradually weakened.