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Investigations on the drift of piles subjected to cyclic lateral loading with a changing loading direction and on the reduction of the drift

改变荷载方向的循环侧向荷载作用下桩的漂移及减小漂移的研究

基本信息

批准号：
163167571
负责人：
Professor Dr.-Ing. Jürgen Grabe
金额：
--
依托单位：
Institut für Geotechnik und Baubetrieb B-5
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/163167571?language=en
关键词：
Investigations drift piles subjected cyclic

项目摘要

Cyclic lateral loading of a pile will result in an accumulation of displacement and rotation of the pile. The accumulation can accelerate, if the load is changing its direction during the cyclic loading. Such a loading situation will occur i.e. from wind and wave loading on an offshore monopile. Preliminary studies and the results from the first project stage have shown an increased accumulation. Here, mainly 1g and ng model tests were performed. The second project stage is going to use a different approach on the drift phenomenon. Numerical studies using the finite element method (FEM) and element tests (simple shear tests with changing shearing direction) will be performed. They will complement the previous testing programme and will allow a wider interpretation of the results. The simple shear testing will link the pile results more closely to the question of the memory of the soil. The numerical simulation of these laboratory tests will prove the capability of the FEM and the constitutive model with respect to complex loading histories and loading paths. Furthermore, a prototype will be simulated with the FEM to evaluate the methods capabilities. The spatial variability of the void ratio will be considered to model realistic conditions. This soil inherent anisotropy might help to produce pile displacements that are non-parallel to the loading direction and thus reproduce the results from the model tests.

桩的循环侧向荷载会引起桩的位移和转动的累积。在循环加载过程中，如果载荷改变方向，则积累会加速。海上单桩在风浪作用下会发生这种荷载情况。初步研究和项目第一阶段的结果表明，积累有所增加。这里主要进行1g和ng模型试验。第二个项目阶段将使用不同的方法来研究漂移现象。采用有限元法（FEM）和单元试验（改变剪切方向的简单剪切试验）进行数值研究。它们将补充以前的测试程序，并允许对结果进行更广泛的解释。简单的剪切试验将把桩的结果与土的记忆问题更紧密地联系起来。这些室内试验的数值模拟将证明有限元和本构模型在复杂加载历史和加载路径下的能力。在此基础上，对一个原型进行了有限元仿真，以评价该方法的可行性。将考虑孔隙比的空间变异性来模拟现实条件。这种土的固有各向异性可能有助于产生与荷载方向不平行的桩位移，从而再现模型试验的结果。