A standard physical model of beach profiles was established based on the morphological features of the erosion section of Benin beach. The wave propagation and evolution laws, along with pore water pressure response characteristics, were investigated through physical tests of wave shoaling and breaking on a slope. Wave shoaling, breaking, and liquefaction during wave propagation were analyzed. The findings indicate a substantial increase in wave height as it propagates near the sandbar; wave propagation deformation increases with rising incident wave height. Nonlinear parameters of the wave continually increase during onshore propagation and attain critical values close to the sandbar, resulting in breaking. With increasing heights and periods of the incident wave, the wave-breaking zone shifts seaward progressively, with long-period swell more prone to breaking than short-period storms. As the proportion of swell increases, the breaking wave occurs earlier, characterized by spilling breakers. Additionally, abrupt changes in waveform result in a sharp increase in vertical pore pressure gradient near the sandbar, affecting soil effective weight. The higher the incident wave height, the larger the horizontal pore pressure gradient, increasing susceptibility to liquefaction. Furthermore, bimodal spectrum waves with 50% wind wave proportion cause the largest horizontal pore pressure gradients and most significant liquefaction, followed by swollen waves; wind waves alone result in the smallest liquefaction.