School of Civil Engineering, University College Dublin, Dublin, Ireland.
SFI Research Centre in Applied Geosciences (iCRAG), Dublin, Ireland.
Sci Rep. 2022 Jun 11;12(1):9691. doi: 10.1038/s41598-022-13962-z.
The long-term sustainability of the offshore wind industry requires the development of appropriate investigative methods to enable less conservative and more cost-effective geotechnical engineering design. Here we describe the novel use of distributed acoustic sensing (DAS) as part of an integrated approach for the geophysical and geotechnical assessment of the shallow subsurface for offshore construction. DAS was used to acquire active Scholte-wave seismic data at several locations in the vicinity of a planned windfarm development near Dundalk Bay, Irish Sea. Complimentary additional datasets include high-resolution sparker seismic reflection, cone penetration test (CPT) data and gravity coring. In terms of fibre optic cable selection, a CST armoured cable provided a reasonable compromise between performance and reliability in the offshore environment. Also, when used as a seismic source, a gravity corer enabled the fundamental mode Scholte-wave to be better resolved than an airgun, and may be more suitable in environmentally sensitive areas. Overall, the DAS approach was found to be effective at rapidly determining shear wave velocity profiles in areas of differing geological context, with metre scale spatial sampling, over multi-kilometre scale distances. The application of this approach has the potential to considerably reduce design uncertainty and ultimately reduce levelised costs of offshore wind power generation.
为了实现海上风能产业的长期可持续发展，需要开发合适的勘察方法，以实现更具成本效益和非保守性的岩土工程设计。在这里，我们描述了分布式声学传感（DAS）作为综合方法的一部分，用于对近海施工的浅层地下进行地球物理和岩土工程评估。在都柏林湾附近的一个计划中的风电场开发项目附近的几个地点，使用 DAS 采集主动 Scholte 波地震数据。补充的附加数据集包括高分辨率电火花地震反射、圆锥贯入试验（CPT）数据和重力取芯。在光纤电缆选择方面，CST 铠装电缆在性能和可靠性方面提供了合理的权衡，适用于近海环境。此外，当用作震源时，重力取芯器可以比空气枪更好地分辨基阶 Scholte 波，并且在环境敏感区域可能更适用。总体而言，DAS 方法在快速确定不同地质背景区域的剪切波速度剖面方面非常有效，具有米级空间采样，覆盖数公里的距离。这种方法的应用有潜力大大降低设计不确定性，并最终降低海上风力发电的平准化成本。
