In this paper is discussed the influence of the parameters such as pile side negative frictional resistance, pile-soil damp, size effect of pile, ground load and pile-soil mass on the dynamic stability of foundation pile under vertical dynamic load.

By a long-term soaking test observation and measurement of a pile embedded in expansion soil ground,the pile-soil interaction and a series of pile working characteristics were obtained such as pile settlements,distribution of axial force and lateral friction along pile shaft,foundation swell-shrink and their time-related characteristics,etc under the simulative rainfall condition.

The calculated friction distribution and the limits of lateral friction of the project testing pile come as a result of practical examples of internal strain testing data of sliding micrometer in engineering pile.

In the analysis,the excess earth pressure and the lateral friction between shield skin with surrounding soil are taken into account.

Research on mechanism of skin friction of cast-in-place piles;

The load-settlement relationship of skin friction q of every part of squeezed branch and corresponding settlement s of plate pile is presupposed as hyperbolic function,the necessary parameters are obtained based on the measured data,and compared with q-s relationship of measured every part.

Based on the analysis of hyperbolic model of skin friction,this paper introduces in-situ static test results of cast-in-place piles conducted in some place of Shanghai.

Through examples of anti-float pile supporting capacity changes,this article analyzes the supporting wall with pile-pouring method,elaborates the mud opposite side friction influence as well as the rule of supporting capacity of pile changes,and proposes a corresponding improvement and optimized suggestion to the phenomena of this kind.

The distribution rule of axis force and friction is studied basing on the stress values by test of anchor in PARS in Handan.