Soil Side Of The Weathered Granite Pile Skin Friction Pilot Study

The research and test of the ultimate bearing capacity of single pile, especially of the determining of skin friction of a expressway's completely weathered granite foundation, was carried out on the basis of previous researches in this paper. The following main contents are included in this paper: the research on load transfer mechanism of piles under axial load, time-dependent effect on skin friction, pile-soil interaction, axial dead load and dynamic load test of the bearing capacity, friction between pile and soil in laboratory, the skin friction's empirical calculating methods, finite element analysis of the single pile's force-bearing state and so on. Actual measurement data of the pile's load bearing capacity and skin friction is obtained by dynamical load test and static load test. The changed relationship of single pile's quality and skin friction with respect to the interregna is determined through low strain method; the pile's skin friction is obtained by pile-soil friction tests in laboratory and by empirical equation. The finite element method is applied to simulate the force acting on pile. Through actual measurement data in test above, the single pile's bearing capacity, end bearing capacity and skin friction is obtained. In addition, it is found that most of load is supported by pile-toe, which is caused by the stress concentration, through finite element analysis. And that is agrees with the test results.