Numerical Modeling of Excavation Process in Dredging Engineering

Abstract

The increase of world population has been requiring more and more lands for human activities, which is why the world dredging market has been significantly growing up during the past 20 years. In dredging engineering, underwater excavation process is one of the major procedures which involves complicated physics, no matter it is sand, clay or rock on the seabed. It is important to reasonably estimate the cutting force needed on the excavator blade, which will help to improve the design and reduce the wear of the equipment so that higher working efficiency can be achieved. However, it is known that the cutting force is greatly influenced by the local water pressure especially in deep water. The fluid flow will change the pore pressure distribution and meanwhile apply certain force to the solid particles. Since the experiments to measure the cutting force are expensive, a numerical model is then needed to describe the physics in it. In this paper, the author tends to use the discrete element modeling to describe the solid particle movement and particle-particle interactions, and the finite volume method to calculate the fluid pressure distribution and flow velocity. Besides, a coupling deck is used between the two models to exchange the information to describe the fluid-solid interaction. This research has proven the feasibility of applying such a method in the underwater excavation process. Further calibration and validation are still necessary depends on the soil properties of the seabed.

Discrete Element Simulation of Conical Pick’s Coal Cutting Process under Different Cutting Parameters

“…Particle Flow Code (PFC) was used to study the cutting force of the picks in linear [21][22][23] and rotary [1,24] cutting process when the cutting thickness was constant and to develop the crack propagation [22,23,25] of coal and rock in the linear cutting process. Extended Discrete Element Method (EDEM) was used to establish linear conical pick cutting coal model to study the cutting process with different cutting thickness and different installation angles [26], which showed that the cutting force of conical pick increases linearly with the cutting thickness and varied nonlinearly with the installation angle.…”

“…In the coal mining operation, conical picks, installed on the shearer drum at different installation angles, are driven by traction speed of the shearer and the angular velocity of the drum to cut the coal. However, the cutting condition, like the prolate cycloid cutting trajectory and the varying cutting thickness, is not distinctly considered in the above scholars' research [21][22][23][24][25][26] based on simplified assumptions. Based on the coal mining operation, this paper simulated the coal cutting process of conical pick at various traction speed, drum angular velocity, and installation angle in EDEM, to analyze the phenomenon of coal fragmentation and the cutting force of conical pick, as well as the relation between cutting force and the cutting parameters mentioned above.…”

Modelling and Simulation of a Mining Machine Excavating Seabed Massive Sulfide Deposits

“…Chen et al established a numerical model of the dredging excavation by using both the discrete element method (DEM) to model the solid particles and the finite volume method to compute the fluid pressure [10]. In addition, studies have been carried out for the rock breaking simulation in atmospheric circumstances.…”

An Analytical Model for Rock Cutting with a Chisel Pick of the Cutter Suction Dredger

“…Even though dredging operations with a CSD are performed under water pressure, a limited water depth does not cause hyperbaric conditions [39]. In addition, the results in [40,41] show that However, Evans' model [20] and Nishimatsu's model [26] for rock cutting with a chisel pick are developed by two-dimensional analysis. They are only suitable for practical rock cutting in shallow cutting depths (the ratio of the cutting width to cutting depth is very large).…”