深海重力锚在黏土中承载性能的模型试验

Model Test on Bearing Capacity of Deep Sea Gravity Anchor in Clay Soil

确定重力锚在黏土中的水平承载力对海洋平台重力锚锚固基础的设计具有重要意义。基于模型试验确定不同类型带有复杂剪力键的重力锚在不同黏土中的水平承载力,通过建立重力锚承载力的锚-土相互作用有限元模型,验证有限元方法的可行性。进而探究重力锚在黏土中拉动时土体的破坏形式,分析不同类型重力锚在黏土中的适应性。试验结果表明,在重力锚运动时土体的破坏形式主要有整体的滑动破坏和局部的剪切破坏,破坏的位置不局限于土体与锚接触的土层,在深度和宽度方向都有一定的延伸;土质内摩擦角对重力锚承载力影响较大,增大近1倍的内摩擦角可使重力锚的承载力增幅超过100%。

It is very important to determine the horizontal bearing capacity of gravity anchor on clay for the design of gravity anchor foundation of offshore platform.Based on the model test,the horizontal bearing capacity of different types of gravity anchors with complex shear keys on different clays is determined,and the finite element model of anchor-soil interaction is established to verify the feasibility of the finite element method.This paper explores the failure mechanism of the soil when the gravity anchor is pulled on the clay,and analyzes the adaptability of different types of gravity anchor on the clay.The test results show that the main failure modes of soil are overall sliding failure and local shear failure.The failure position is not only limited to the soil layer in contact with the anchor,but also extends in depth and width.The internal friction angle of soil has great influence on the bearing capacity of gravity anchor.The bearing capacity of the gravity anchor can be increased by more than 100%by nearly doubling the internal friction angle.