Abstract
As one method to reduce negative skin friction on a pile it can be considered that the pile is tapered. This principle is based on the fact that, when the surrounding soil settles down relatively faster than the pile, it separates off from the pile surface. In order to verify this fact, model tests of negative skin friction were done, using four piles having the following kinds of taper; 10 to 1000, 5 to 1000, 1 to 1000, and 0 to 1000, i. e. straight. For those tests a small steel bin was used where a base plate supported by piston cylinders was lowered as slowly as possible so that the sand filled there could settle down, developing negative skin friction on the pile surface.As a result, it could be concluded that the negative skin friction could be reduced by roughly 90% for 10 to 1000, 80% for 5 to 1000, and 50% for 1 to 1000 in comparison with a straight pile.
