Based on the field testing data of 82 piles in 40 sites,through the study on the mobilization characteristics of pile total skin friction with pile head settlement,it is found that:(1) the total skin friction of 13 piles degrade in 36 piles whose total skin friction have arrived at ultimate state;(2) there are four types for pile total skin friction′s degradation,i.

It is thought that the reaming-angle of reaming bit should be less than 25 degree, the rock compression strength under the pile end should be no more than 6MPa, and lateral frictional force and end resistance of pile should be adjusted when vertical carrying capacity is calculated.

The study of rock-socketed pile side resistance character;

This paper has expatiated follow things:obtaining of pile side resistance;ingredient of impacting pile side resistance;pile side resistance strengthen effect and degradation effect which discovered in some home and oversea datum.

Based on the model test and engineering practice, the basic rule of pile side resistance enhancement has been summarized.

Research on interaction between resistance at pile and lateral resistance of pile;

Study of pile shaft resistance is a key point of the research on the pile bearing performance.

This paper elaborates a new theoretical problem on the behavior of piles under load, namely, the influence of soil strength underneath a pile on pile shaft resistance.

So far, more and more scholars have been attracted by the phenomenon, that character of soil under the pile toe has influence on the development of pile shaft resistance within a certain scope near pile toe.

The behavior by top loading and the partake scale of shaft resistance and end resistance are analyzed in the pape r.

According to the analyzed results of twelve dynamic loading tests on rock\|socketed piles,the behaviors of shaft resistance of the socket and toe resistance are discussed,a relationship of shaft resistance of socket to the length of socket and the rock strength and the construction of piles is presented.