Abstract: By measuring the distribution of pore water pressure field in soft clay during DC,the variation of pore water pressure with depth and time in the foundation of soft clay is analyzed,the development of liquefaction space in muck during DC is studied, and furthermore, the effective influence depth and scope are analyzed in this paper. The results are generally consistent with the results calculated by the method of pseudo static method. A method to choose the number of DC, the spacing of DC, the effective influence depth and other parameters through the experiment is presented.