Abstract
Experimental tests have been conducted on mainly open-ended pilemodels driven into fine-grained sand (soil) by low-frequency vibratory excitations. The minimum input force amplitude that causes a pile to penetrate the soil and the optimum amplitude that ensures the quickest penetration of the pile to the ultimate depth have been determined. Postoptimum force levels have been found to induce a high impactive reaction at the pile tip (i.E., Dynamic tip resistance), andthis phenomenon has been investigated. A mathematical theory to predict the dynamic tip resistance is proposed. Piles with various tip configurations have been tested. This paper appears in transportation research record no. 1331, Integrity testing of foundations 1991