Abstract: A series of experiments in pile foundation was performed with a variety of pile layout spacing, embedded depth, number of piles as well as position of pile cap but with same soil-sandy clay. Measurements of reactions and deformations of piles and nearby soil were conducted.Based on tests rasults some rules concerning ths behaviour of looting-pile-soil system during working were founded, and optimized dimensions and bearing capacity of the system were suggested. These results have been used in compilation of china design cods for drydock (1985 edition).