利用三维极限分析软件Optum G3,探究斜坡海床上刚性单桩基础水平承载失稳机理,分析单桩基础极限承载力随基础长径比、桩-土界面摩擦系数、土体强度、斜坡坡度和荷载加载方向的变化规律。研究发现,当单桩基础长径比较小时,破坏模式主要包括近泥面处的破坏楔体和底部的球型破坏;随着基础长径比的增加,楔体和球型破坏模式之间出现全流动破坏模式,破坏模式为：楔体-全流动-球型破坏模式;随着长径比进一步的增加,在球型破坏底部形成另外一个全流动破坏模式,破坏模式由上到下依次为：楔体-全流动-球型-全流动破坏模式。水平承载力系数Np随着基础长径比的增加先减小后增大,最后趋于稳定;随着基础桩-土界面摩擦系数的增加逐渐增大;随着土体强度梯度的增加逐渐减小;随着荷载加载方向的增大而增大;双侧破坏模式对应承载力系数比单侧破坏模式对应的承载力系数,按照单侧破坏模式进行承载力设计更加安全。
Abstract
The failure mechanism of horizontally loaded rigid monopile on slope seabed is investigated by using 3-D limit analysis software Optum G3. The failure mechanism and ultimate bearing capacity of monopile with various aspect ratios, pile-soil interface friction coefficient, soil strength and slope angles are analyzed. It is found that when the aspect ratio of monopile is small, the failure modes mainly include wedge failure at shallow seabed and spherical failure in deep soil. With the increase of aspect ratio of the monopile, the full flow failure mode appears between wedge failure and spherical failure. With the further increase of aspect ratio, another full-flow failure mode is formed below the spherical failure mode. The corresponding horizontal bearing capacity coefficient （Np） firstly decreases and then increases with the increase of aspect ratio of monopile, and finally keeps constant. Furthermore, the factor Np increases with the increase of friction coefficient and loading angle, but decreases with the increase of soil strength gradient and slope angle. Additionally, the factor Np of the single-sided failure mode is smaller than that of two-sided failure mode, indicating that it is safer to design the ultimate bearing capacity of the monopile according to the single-sided failure mode.
关键词
海上风电 /
承载力 /
数值分析 /
斜坡海床 /
单桩基础
Key words
offshore wind power /
bearing capacity /
numerical analysis /
slope seabed /
monopile
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基金
中国博士后科学基金（2023M733881）; 国家自然科学基金（52078483）
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