Abstract
On the preceding report part-1, the principle of plugging effect and bearing mechanism of steel pipe pile was theoretically illustrated. As a serial instalment, several practical problems was discussed on this paper. Coefficients of friction between pile and soil and lateral pressure of soil which were unable to be known by the usual method of soil test, could be obtained by the experimental work with the original instruments. By the use of these factors obtained by the complementary test, the theoretical estimates of the ultimate bearing capacity of pipe piles were proved on good agreement with the observed practical field test data. A large size pipe piles driven to subgrade without enough depth of penetration cannot be expected to from a complete plug at the top of pile. Assume that a complete plug are always pproduced at the pile top, the estimates from past bearing capacity formulas are remarkably contradictory to actual value. This is very dangerous to planning of pipe pile foundation. By the theoretical mechanism described on this paper, it will enable to estimate the ultimate bearing capacity of pipe pile with practical accuracy.
