An experimental research of vibration pore water pressure of remolded silt under low confining pressure: A case from Chengbei sea area

A triaxial experiment for vibration pore water pressure of remolded silt was carried out in Chengbei sea area under low confining pressure and consolidated undrained conditions. The results indicate the pore water pressure curve of the silt shows two forms at low confining pressure, depending on the axial vibration stress and/or critical cyclic stress of the silt. After the vibration pore water pressure data was normalized, it is found that the vibration pore water pressure of the silt at low confining pressure changes following a pattern of exponential function and the clay content does not affect much the model except the two experimental parameters a and b. Study of the factors that affect pore water pressure shows that even a small amount of clay may increase the growth rate of pore pressure in remolded silt but there is a threshold of about 10~11%. When the clay content exceeds this threshold the rate of pore pressure will significantly slow down. There is a threshold of vibration frequency in a figure of 0.2 Hz. The increase of the vibration frequency will slow down the growth rate of pore water pressure when the vibration frequency is less than 0.2 Hz but accelerate with the increase in vibration frequency when the vibration frequency is greater than 0.2 Hz.