Study on the Mechanism of Squeezing Silt by Riprap of Rubble Mound Breakwater Based on the Particle Flow Code.

Rubble mound breakwater (RMB) is a kind of sloping breakwater built by squeezing silt by riprap, and the effect of squeezing silt by riprap has a significant influence on the stability of RMB. This paper simulated the dynamic process of squeezing silt by riprap based on the particle flow code and studied the influences of the silt mixed sand layer's thickness, the riprap height, and the riprap radius on the depth of squeezing silt. In the squeezing silt test by single riprap, the depth of squeezing silt increases exponentially as the thickness of silt mixed sand layer increases and increases linearly as the riprap height and the riprap radius increase. In the process of squeezing silt by complete ripraps, the depth of squeezing silt increases linearly as the thickness of silt mixed sand layer increases, increases exponentially as the breakwater height increases, and increases quadratically as the maximum riprap radius increases. Besides, through analyzing the vertical displacement curve of the characteristic particles, the process of squeezing silt by riprap is divided into three parts: instantaneously squeezing silt, squeezing silt by kinetic energy transfer, and squeezing silt by the gravity of riprap heap. The mechanism of squeezing silt by riprap is revealed. This study can well guide the riprap construction of RMB and estimate the amount of riprap, which has greatly practical significance. [ABSTRACT FROM AUTHOR]