砂土中裙式吸力基础注水拔出渗流规律数值模拟  

Numerical simulation on seepage field around modified suction caisson in saturated sand during extraction by reverse pumping water

作　　者：李佳禧 张雨坤[3] 李大勇 LI Jiaxi;ZHANG Yukun;LI Dayong(College of Civil Engineering,Fuzhou University,Fuzhou 350108,China;PowerChina Huadong Engineering Corporation Limited,Hangzhou 311122,China;Key Laboratory of Civil Engineering Disaster Prevention and Mitigation,Shandong University of Science and Technology,Qingdao 266590,China;College of Pipeline and Civil Engineering,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]福州大学土木工程学院,福建福州350108 [2]中国电建集团华东勘测设计院有限公司,浙江杭州311122 [3]山东科技大学山东省土木工程防灾减灾重点实验室,山东青岛266590 [4]中国石油大学(华东)储运与建筑工程学院,山东青岛266580

出　　处：《人民长江》2022年第11期163-169,共7页Yangtze River

基　　金：山东省自然科学基金项目(ZR2019BEE007);国家自然科学基金项目(51879044);山东科技大学科研创新团队计划项目(2015TDJH104)。

摘　　要：裙式吸力基础是一种新型海上风电基础形式。相比于传统吸力基础,裙式吸力基础具有更高的承载力和控制基础变形的能力。当海上风电上部结构达到服务年限或沉贯安装失败时,可通过向吸力基础桶内注水实现基础的拔出回收和重复利用。为此针对裙式吸力基础拔出过程,通过开展数值分析研究其在饱和砂土注水拔出过程中的渗流场分布规律。结果表明:注水拔出过程中,基础发生由内而外的渗流,导致基础内部土体向下移动,有效应力和侧壁摩阻力增大,基础外壁有效应力与侧壁摩阻力降低。注水拔出过程中,裙式吸力基础渗流影响区域与传统吸力基础差别较小。裙式吸力基础与传统吸力基础在水头等势线分布规律、土体孔压及有效应力的变化趋势上基本一致,但量值较传统吸力基础显著提高。拔出过程中,裙式吸力基础的“裙”结构内部产生负压,与主桶内部的压力正相反。The modified suction caisson(MSC)is a novel type of offshore wind turbine foundation.Compared with the regular suction caisson(RSC),the MSC can effectively increase the bearing capacity and limit deflection capacity.When the service of an offshore wind turbine is terminated,or the installation of suction caisson is failed,the suction caisson should be extracted by reversing pumping water into the caisson.Numerical simulations are carried out to investigate the seepage field distribution around the MSC and RSC during the extraction by reverse pumping water into the caisson.It is found that during extraction,seepage occurs in sand both in and around the suction caisson.Water flows from inside of the caisson to the outside soil,thus leading to the downward movement of soil and increases of effective stress and shaft frictional forces in the suction caisson and the decreases of effective stress and shaft frictional forces at outer wall of suction caisson.During the extraction,the difference between the influenced areas of seepage around the MSC and RSC is relatively small.The trends of distributions of the hydraulic head equi-potential lines,excess pore pressure and effective stress of the MSC are the same as those of RSC.However,the values of the above parameters for the MSC are higher than those for the RSC.During extraction,negative pressure is generated in the internal compartment,which is reverse to the pressure in major caisson.

关 键 词：裙式吸力基础 注水拔出 渗流 数值模拟 

分 类 号：P75[天文地球—海洋科学]