To investigate the bank protection performance of polyvinyl chloride (PVC) sheet piles subjected to water level fluctuations, this study systematically examined the mechanical responses of PVC sheet piles with varying stiffnesses and their influence mechanisms on bank slope stability using a custom-designed water level control device. The variation laws of the pile top displacement, lateral earth pressure, bank slope moisture content, and slope top settlement were revealed. Furthermore, the stability of the PVC sheet pile-protected bank slope was analyzed through numerical simulations. The results indicate that the initiation time of the slope top settlement is significantly delayed by the implementation of sheet piles with different stiffnesses. The maximum settlement decreases as the sheet pile stiffness increases; notably, the 12 mm thick sheet pile reduces the ultimate settlement by 52.0%. Correspondingly, the peak horizontal displacement at the pile top decreases from 7.8 mm to 3.4 mm with the increase in stiffness. In addition, the 4 mm thick sheet pile can release soil stress through yielding deformation, resulting in a nonlinear variation in lateral earth pressure characterized by an “initial increase–brief decrease–subsequent increase” pattern. Conversely, the deformation of the 12 mm thick sheet pile is restricted, impeding stress release and causing the lateral earth pressure to increase continuously, reaching 13.3 kPa. Finally, numerical simulations further reveal that a faster water level rising rate leads to a more significant improvement in bank slope stability, yielding a maximum safety factor of 7.088, while the maximum horizontal displacement decreases from 468.2 mm during a slow rise to 124.1 mm during a rapid rise.
Tao et al. (Sat,) studied this question.