【作者】 张浦阳；

【导师】 丁红岩；

【作者基本信息】 天津大学 ， 结构工程， 2004， 硕士

【摘要】 本文针对海上吸力锚基础这一新型海洋平台基础形式研究中面临的吸力锚负压沉贯下沉中锚内产生土塞现象这一吸力锚基础施工中的关键问题，通过对吸力锚渗流场的数值模拟，运用圆形刚性颗粒模型的离散单元法对锚体周围土体进行数值模拟，编制了用来计算吸力锚负压沉贯中的土塞高度的计算程序（SPSA）。吸力锚沉桶施工中，桶内土面在桶内外压力差和渗流力等作用下向上升高形成土塞，并在沉桶施工后期提前和桶顶盖接触，导致吸力锚无法继续下沉。土塞现象的发生与施工地点的土壤类别以及土质特点密切相关。除此之外，影响土塞的因素还包括施加负压吸力的大小、沉桶速度、初始封闭条件、桶边壁摩擦力的大小以及桶的几何尺寸等。通过本文编制的程序，分别模拟了在粉质粘土，粉土和砂土等三种土质条件下吸力锚下沉过程中土塞的形成情况，并与Algor软件计算结果和试验结果进行了比较，说明了离散元方法在此问题运用的合理性。通过分析可以发现负压吸力和渗流力是造成土塞现象的重要原因。土的种类及其基本物理参数对土塞高度也有一定的影响。本文的研究对吸力锚负压沉贯过程中负压的控制和吸力锚基础设计和施工都有一定的指导意义。更多还原

【Abstract】 Suction anchor is a new style of offshore platform foundation. The soil plug phenomenon is the key problem during the process of suction penetration of suction anchor in construction. By numerical analysis of seepage field of suction anchor and discrete element method of round rigid element simulating soil around the anchor, the relevant program (SPSA) is written for computing soil height during suction penetration of suction anchor. During the construction of suction anchor by suction penetration, the soil plane inside the anchor would be upwards forced by the difference of suction inside and outside of the anchor and seepage force inside the soil. Therefore, soil plug will touch the top of the anchor and prevent the penetrating of suction anchor in advance. The height of soil plug is influenced by the sorts of soil besides the suction magnitude, the velocity of penetration, original close conditions, friction magnitude of edge of suction anchor and the dimension of suction anchor, etc.The program (SPSA) mentioned above simulates the soil plug height in the 3 different soil of silty clay, silty and sand during the suction penetration. Through comparing the results of program with the results of software of Algor and test records, it is proved that the results are reasonable and the discrete element method is available for simulating soil in computing height of the soil plug. By the analysis of the results, the conclusion is that the suction force is the main reason contributed for the soil plug as well as the seepage force. The sort of soil and its physical parameters, to some extent, is some reason, too. The research of soil plug inside suction anchor is a meaningful reference for the suction control during the process of suction penetration and the suction anchor’s design and construction.更多还原