Design procedures for embedded structure considering seabed gonging of deformed sea ice

考虑变形海冰海底挖掘的嵌入式结构设计程序

基本信息

批准号：
15360259
负责人：
SAEKI Hiroshi
金额：
$ 9.73万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15360259/
关键词：
Pipeline Sea ice Scour Gouge Scale effect Sub-scour deformation Stress within seabed Burial depth Probability of failure 海底構造物固結層非固結層 sub-scour deformation

项目摘要

We developed a simulation method of Ice Scour Event considering probability distributions of various environmental parameters. As a result of calculations made under various conditions, order similar to those in the field observation data -the scour length of several tens of meters to several kilometers and the scour depth of several tens of centimeters to several meters -were found. Furthermore, due to the similarity to (reproducibility of) the comprehensive tendency/property of actual scour events, results that compared favorably with field observation results were obtained. Using the simulation results we then can estimate the probability of failure of structures (probability of contact between structure and ice keel) according to burial depth. From the basis, we finally proposed an estimation method of optimal burial depth of seabed structures such as pipeline against ice scour event. It can be presumed that the above concept is based on a reliability design through which safety assessment for the case in which uncertainties surrounding the environment are prominent is possible.Also, we made a medium-scale model experiment as well as the small-scale experiment in the last year related to "sub-scour deformation", which means stress transmission or soil deformation within the seabed below the sea ice. From the small-and medium scale model test results, we clarified the scale effects/similarities related to reaction forces and stress distributions within seabed While we made a simple pipeline-response analysis model due to the stress within seabed, we confirmed that calculation results by the model were almost corresponded to measured results. Using this method, we can calculate pipeline-response considering the scale effects. We also attempted to estimate the optimal burial depth of a pipeline considering the sub-scour deformation in an actual sea area. As a result, we found that it would be enough to bury a pipeline at 1.6 times deep as the scour depth.

考虑到各种环境参数的概率分布，我们开发了一种冰搜索事件的模拟方法。由于在各种条件下进行的计算，类似于现场观察数据的订单 - 几十米至几公里的冲刷长度以及几十厘米至几米的冲刷深度 - 发现了。此外，由于与实际冲刷事件的全面趋势/特性相似，因此获得了与现场观察结果相比的结果。然后，使用仿真结果，我们可以根据埋葬深度估算结构失败的可能性（结构和冰龙骨之间的接触概率）。从基础上，我们最终提出了一种估计方法，即海床结构的最佳埋葬深度，例如反对冰雪事件的管道。可以假定上述概念是基于一种可靠性设计，通过该设计，对环境周围不确定性的安全性评估是可能的。此外，我们进行了一个中等规模的模型实验以及去年的小规模实验，与“亚跑道变形”相关，这意味着压力传播或土壤下方的海底冰层。从中等规模的模型测试结果中，我们阐明了由于海床内应力而制作的简单管道响应分析模型，与海床内的反作用力和应力分布相关的比例效应/相似性，我们证实了该模型的计算结果几乎对应于测量结果。使用此方法，我们可以考虑规模效应来计算管道响应。考虑到实际海面的子筛选变形，我们还试图估计管道的最佳埋葬深度。结果，我们发现将管道埋在1.6倍的1.6倍之后，这是足够的。