Probabilistic capacity analysis of suction caissons in spatially variable clay
Probabilistic capacity analysis of suction caissons in spatially variable clay
复制标题
DOI：
10.1016/j.compgeo.2016.06.001
复制
发表时间：
2016-12
影响因子：
5.3
通讯作者：
T. Charlton;M. Rouainia
中科院分区：
文献类型：
--
作者：
T. Charlton;M. Rouainia
在海上能源生产中，越来越多地使用吸力沉箱来系泊深水浮式设施。吸力沉箱的承载能力取决于系泊绳的角度，通常用垂直-水平(VH)载荷相互作用图或破坏包络来描述。这些包络通常是用数值方法定义的，使用确定性的土壤参数，忽略了海底沉积物的自然空间变异性。本文利用随机场对空间变异性进行建模，并与有限元分析相结合，得到承载能力的概率特征。考虑了海相粘土所特有的强度随深度的增加。提出了一种使用核密度估计的非参数方法来构造概率VH故障包络，该包络允许选择与可接受的风险水平相关联的适当包络进行设计。对自相关距离的研究表明，垂直自相关距离比水平自相关距离对持有量变化的影响要大得多，在近海应用中应谨慎选择。
Suction caissons are increasingly used in offshore energy production to moor floating facilities in deep water. The holding capacity of a suction caisson is dependent on the angle of the mooring line and is often described in terms of a vertical-horizontal (VH) load interaction diagram, or failure envelope. These envelopes have commonly been defined by numerical methods using deterministic soil parameters, ignoring the natural spatial variability of seabed sediments. In this paper, spatial variability is modelled using a random field and coupled with finite element analysis to obtain a probabilistic characterisation of holding capacity. The increase of strength with depth that is characteristic of a marine clay is taken into account. A non-parametric approach using kernel density estimation is presented for constructing probabilistic VH failure envelopes that allow an appropriate envelope, associated with an acceptable level of risk, to be selected for design. A study of the autocorrelation distance, a quantity often difficult to obtain accurately in practice, has shown that the vertical autocorrelation distance has a much greater influence on the variability of holding capacity than the horizontal and should be carefully chosen in offshore applications.