It is well known that the load for the bearing stratum is transmitted progressively (during the loading process stage when the load magnitude vary from 0 till its final magnitude F), at first through the shaft and only after the tip is "employed", then load is transmitted via the shaft and the tip.
The classical patterns of the pile bearing stratum failure, proposed by the different researches which were summarized by Vesic (1967), are shown in Fig.
For this reason the patterns of pile bearing stratum failure has to be chosen very accurately.
It is well known that cone penetration is indirect method of total soil response evaluation, which actually does not fully describe the stress state of bearing stratum.
This effect appears due to the bearing stratum deformation and failure mechanism.