Experimental study of erosion threshold of reconstituted sediments

• Published in: Volume 7: CFD and VIV; Offshore Geotechnics
• Main Authors: Ye ZH, Cheng L, Zang ZP(臧志鹏), Ye, ZH (reprint author), Univ Western Australia, Sch Civil & Resource Engn, Perth, WA 6009, Australia.
• Format: Other/Unknown Material
• Language: English
• Published: AMERICAN SOCIETY OF MECHANICAL ENGINEERS 2011
• Subjects: Arctic Engineering; Erosion; Mixtures; Sedimentology; Shear Stress; Coarse Particles; Cohesive Sediments; Equilibrium Modes; Erosion Characteristics; Erosion Thresholds; Experimental Studies; Mass Content; Mud Weights; Natural Sediments; Predicting Models; Research Efforts; Seabed Sediments; Test Condition; Testing Facility; soil erosion; aggressiveness; sedimentation; experimental investigations; geologic erosion; weathering; rocks; shoreline erosion; coastal erosion; beach erosion; shoreline retreat; wind erosion; dissolution; erosion (deutsch); erosion (francais); scars (geology); erosion (geology); 土壤侵蚀; accelerated erosion; soils > erosion; soil loss; 加速侵蚀; 土壤侵蚀[学]; 土壤流失; 侵蚀; etching; aggression (psychology); Arctic
• Online Access: http://dspace.imech.ac.cn/handle/311007/46848; https://doi.org/10.1115/OMAE2011-50067

Understanding of fundamental erosion characteristics of seabed sediments on which pipelines and other structures are founded is critical for the design of these facilities. The erosion threshold condition of cohesive sediments is not well understood because of the complexity and variability of natural sediments. Most of the existing methods for evaluating the erosion behaviours of seabed sediment are often applicable to the certain particular sediment types and test conditions. There appears to be a need for more research efforts in this area. In present research, the threshold of motion of four moderately consolidated mixtures was tested under unidirectional currents using a testing facility. Three threshold shear stress increase modes were observed, including initial increase mode, steady increase mode and equilibrium mode as mass content of mud Pm increases. A dimensionless threshold shear stress t is proposed to quantify the shear strength of these reconstituted mixtures, coupled with variation of coarse particle size. Finally, a predicting model is proposed to illustrate the trend of erosion threshold of the four mixtures as a function of mud weight content. Further understanding of erosion threshold can rely on the various consolidation conditions and different coarse and fine materials inputted in the mixture.