PREDICTION OF TIP RESISTANCE FROM PILE DYNAMICS

This report undertakes to evaluate conditions at which input power to a pile is said to reach optimum level, and to study the dynamics of the pile if the input power level is increased beyond the optimum value. The study is confined to low frequency vibropile driving using closed tip model piles and fine grain sand. For the post optimum condition, the pile induces relatively large impactive reaction (tip resistance) from the soil, which may cause damage to the embedded lip. A simple nonlinear mathematical theory for the impactive reaction or tip resistance is proposed. Experimental and theoretical results have good agreement.