桶型基础负压沉贯阻力及渗流场特性研究  

Study on penetration resistance and infiltration field characteristics of bucket foundation

作　　者：徐成根 江海涛 张雅茹 吴新云 高鹏 孙德成 王辉剑 XU Chenggen;JIANG Haitao;ZHANG Yaru;WU Xinyun;GAO Peng;SUN Decheng;WANG Huijian(CGN Rudong Offshore Wind Power Co.,Ltd.,Nantong 226000,Jiangsu,China;College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310000,Zhejiang,China;PowerChina Huadong Engineering Corporation Limited,Hangzhou 311500,Zhejiang,China)

机构地区：[1]中广核如东海上风力发电有限公司,江苏南通226000 [2]浙江大学建筑工程学院,浙江杭州310000 [3]中国电建集团华东勘测设计研究院有限公司,浙江杭州311500

出　　处：《水利水电技术（中英文）》2024年第6期182-195,共14页Water Resources and Hydropower Engineering

基　　金：国家自然科学基金(51779220)。

摘　　要：【目的】在桶型基础的安装过程中,施加的负压不仅会给桶基提供向下的驱动力,与此同时负压还会使沉贯的过程中产生由外而内的渗流场,外部海水自桶外绕过端部之后向桶内渗流。为了探究和评估在该渗流场的作用下,周围土壤有效应力发生的变化,以及对桶基内外壁的摩擦力及端部承载力变化的影响,对均质海床和成层海床的沉贯阻力展开研究。【方法】应用有限元软件COMSOL Multiphysics,采用数值模拟的方法,分别建立饱和砂土、黏土以及成层土桶型基础沉贯安装过程中的二维轴对称模型,探究评估在渗流场作用下沉贯阻力的变化情况。【结果】结果显示:渗流场对桶型基础在砂土海床中的沉贯产生了明显的减阻效应,施加负压后沉贯总阻力降低超30%,而对黏土海床的影响较小,均质海床中的渗流场分布具有相似的特性。对于上砂下黏海床,由于黏土层对渗流的抑制,导致沉贯阻力较均质砂土增大20%,上黏下砂海床由于黏土层对负压的削弱,导致沉贯阻力较均质黏土增大36%。【结论】结果表明:施加的负压一方面为桶基提供了竖向力,另一方面减小了沉贯阻力。而成层海床情况比单一砂土、黏土海床更加复杂,在土壤条件分界处各渗流要素发生突变,较易引起桶基内部土壤的破坏。研究成果可对现场安装施工提供更加方便和有效的理论性指导。[Objective]During the installation of bucket foundation,the negative pressure applied not only provides downward driving force for the bucket foundation,but also generates an infiltration field from outside to inside during the penetration process.External seawater infiltrates into the bucket foundation after bypassing the end.In order to investigate and evaluate the changes in the effective stresses in the surrounding soil under the action of this seepage field,as well as the effects on the friction of the inner and outer walls of the barrel base and the changes in the end bearing capacity,a study was carried out to investigate the sedimentation penetration resistance of the homogeneous seabed and the layered seabed.[Methods]In this paper,finite element software COMSOL Multiphysics was used to establish two-dimensional axisymmetric models of saturated sandy soil,clay,and layered soil bucket foundations during penetration installation using numerical simulation,to explore and evaluate the changes in penetration resistance under the influence of the infiltration field.[Results]The result indicate that the infiltration field has a noticeable reduction effect on the penetration of bucket foundations in sandy seabeds.The total penetration resistance decreases by over 30%when negative pressure is applied.However,the impact on clay seabeds is relatively minor.The distribution of the infiltration field in homogeneous seabeds exhibits similar characteristics.For the case of a sandy layer overlying a clay seabed,the presence of the clay layer suppresses the infiltration,Resulting in a 20%increase in penetration resistance compared to homogeneous sandy soil.In the scenario of a clay layer overlying a sandy seabed,the weakening of negative pressure due to the clay layer leads to a 36%increase in penetration resistance compared to a homogeneous clay seabed.[Conclusion]The result show that the applied negative pressure provides vertical force to the barrel foundation on one hand,and reduces the resistance to sinking through o

关 键 词：桶型基础 负压沉贯 数值模拟 渗流特性 沉贯特性 

分 类 号：TV213.4[水利工程—水文学及水资源]