With the GDS dynamic triaxial system

undrained dynamic triaxial tests on the saturated sand with different fines content are performed

and the effects of fines content on evolutionary characteristics of dynamic pore water pressure of saturated sands in the process of liquefaction are analyzed based on Seed pore water pressure stress model. It is found that fines content has great effect on the dynamic pore water pressure of saturated sands by the parameter θ for Seed model. The relationship between parameter θ and fines content isnt linear. Parameter θ decreases with the increase of fines content at first

and then reaches its smallest value when the critical value of fines content is 30%. After that

parameter θ increases gradually with the rise of fines content. According to the experimental study on effects of fines content on evolutionary characteristics of dynamic pore water pressure of saturated sands

the existence of critical fines content with 30% is further proved in the sandy soil used in the test.