Changes of the pore distribution of silty clay under the subway train loads

Vibrations induced by the passage of subway trains are a major concern in urban areas. These vibrations can cause annoyance to people. Meanwhile, they can cause the settlement of tunnels by loading on the structured soft soil around the tunnel. It is known that the engineering behaviors of soft soil are determined by its microstructure. Therefore, the changes of pore distribution under characteristic dynamic loads were studied in this paper through a series of dynamic triaxial tests and mercury intrusion porosimeter tests. It is worth mentioning that the low-order fundamental frequency should be paid more attention to the similar research. Under the dynamic loads, the silty clay and mucky silty clay samples were all compacted. The volume of large pores (pore radius >400 nm) significantly decreased, while the volume of medium and small pores (pore radius <400 nm) increased due to the transformation of large pores. The changes of pore distribution can be well reflected by the fractal dimensions in thermodynamic model.