来流速度和土体强度对黏土质海床管道局部冲刷特性影响研究  

Study on the Influence of Inflow Velocity and Soil Strength on Local Scour Characteristics of the Pipelines in Clay Seabed Environment

作　　者：张美娜 韩翔希 翟煜 齐国胜 任地 蒙占彬 ZHANG Meina;HAN Xiangxi;ZHAI Yu;QI Guosheng;REN Di;MENG Zhanbin(Guangxi Key Laboratory of Ocean Engineering Equipment and Technology,Beibu Gulf University,Qinzhou 535000,China)

机构地区：[1]北部湾大学广西海洋工程装备与技术重点实验室,广西钦州535011

出　　处：《海岸工程》2024年第4期307-320,共14页Coastal Engineering

基　　金：国家自然科学基金项目(52201304);广西科技重大专项项目(桂科AA22068105)。

摘　　要：本文基于SST k-ω模型、Herschel-Bulkley黏土模型和VOF两相流模型建立海底管道局部冲刷的二维CFD模型,以来流速度U和土体强度τ0为变量参数开展数值模拟研究。通过分析管道两侧床面压力特征、冲刷坑形态、冲刷深度历时曲线、管道局部速度分布等内容,探究了不同来流速度(U)和土体强度(τ0)对海底管道局部冲刷特性影响的规律。研究结果表明:①黏土质海床环境下海底管道局部冲刷受来流速度影响显著。随着来流速度的增加,管道局部极限平衡冲刷深度与冲刷坑宽度均增大,平衡冲刷深度增幅与流速增幅的比率整体呈减缓趋势。②黏土质海床环境下海底管道局部冲刷受土体强度影响显著。随着土体强度的增大,海床渗流力减弱,管道局部极限平衡冲刷深度减小,下游沉积丘距离管道轴心越近。当土体强度大于等于300 Pa时,管道底部与海床之间的间隙较难形成。A two-dimensional CFD model for local scour of submarine pipelines is established based on SST k-ω model,Herschel-Bulkley clay model and VOF two-phase flow model.The inflow velocity U and soil strengthτ0 are used as the variable parameters for the study of numerical simulation.By using this model,the law of the influence of different inflow velocities U and soil strengthτ0 on local scour characteristics of the submarine pipelines is studied by analyzing the bed surface pressure characteristics,shape of scouring pit,duration curve of scouring depth and local flow speed distribution on both sides of the pipeline.The results show that the local scour of the submarine pipelines in the clay seabed environment is affected significantly by inflow velocity.With the increase of the inflow velocity,both the local limit equilibrium scour depth and the width of scour pit increase,and the ratio of the increase in equilibrium scour depth to the increase in flow velocity tends,as a whole,to slow down.The local scour of submarine pipelines in the clay seabed environment is affected significantly by soil strength.With the increase of the soil strength,the seepage force of the seabed is weakened,the limit equilibrium scour depth of the pipeline decreases and the mound downstream of the pipeline is closer to the pipe axis.When the soil strength is greater than or equal to 300 Pa,it is more difficult to form a gap between the bottom of the pipe and the seabed.

关 键 词：黏土 来流速度 土体强度 海底管道 局部冲刷 

分 类 号：P75[天文地球—海洋科学]