Experimental study on time-varying failure evolution of armour blocks on sloping breakwaters

Abstract

The time-varying failure evolution is significant for revealing failure mechanism of breakwaters. Physical experiments were conducted to investigate the time-varying failure evolution of armour blocks on sloping breakwaters, and the effects of the block placement density, wave height, wave period, wave impact time, and block type on the stability of armour blocks are discussed. The results showed that the time-varying failure evolution of armour blocks was not uniform with an increase in wave impact time. However, a large-scale rapid damage maybe occur in a certain period of time, which was enhanced with a decrease in block placement density and an increase in the incident wave height and wave period. With the same block placement density, the instability rate with uniform reduction per row was generally lower than that with centralised and decentralised reduction. Furthermore, when the design wave height was increased by less than 30%, the protection effect of the accropode was superior to that of the dolosse. However, the protection effect of the two was opposite when the design wave height was increased by over 30%. The results reveal the time-varying failure law of breakwaters, which will contribute to further study the risk assessment and early warning of breakwater failure.