Development of an active layer seafloor sampler as an add-on unit for portable free-fall penetrometers

水下沉积物动力学影响着海岸带和海洋环境中的许多问题，如海岸侵蚀和演变、海洋斜坡稳定性、通航水深、近海结构物的稳定性以及作为栖息地的海底。关于水下沉积物动力学的悬而未决的问题之一是流动海底表层内的厚度、密度和颗粒分布。该项目旨在开发一种移动式海底沉积物采样器，作为便携式自由落体渗透仪的附加部件。对流动海底沉积物的密度、厚度和沉积学成分进行取样的能力将为在水下地貌和地貌动力学、沉积物动力学、海洋地质学以及沿海和近海工程以及海底岩土工程领域开展新的研究和深入了解铺平道路。这将直接有助于对水下泥沙输运和冲刷的具体和系统的了解，并将填补目前关于推移质输运的知识空白。因此，由此产生的文书可能会启动新的跨学科合作，并解决各种现代环境和社会问题。这一发展也将对首席调查员的职业生涯和后续研究道路产生重大影响，他的工作旨在弥合水下沉积物动力学和岩土工程之间的差距。从事这一开发工作的一名研究生研究助理将接受有关泥沙输送理论和实践、现场海洋岩土技术以及海岸和近海测量的详细教育和培训。事实上，大部分测试将在弗吉尼亚理工大学的校园内进行，这将使其他学生能够洞察情况，可能是完整的课程，并可以轻松地将获得的知识和程序转移到课堂上。特别是，女学生将受益于首席调查员，作为仍由男性主导的海洋技术和近海调查领域中女性研究人员的榜样。移动式海底表层采样器将被开发为便携式自由落体穿透仪的附加部件，该仪器已应用于沉积物动员过程的调查多年。一个带有密封机构的采样管将集成在自由落体渗透仪的钢尖上，建立一个采样单元，允许在进行岩土剖面分析时收集小的沉积物样本。该项目将包括附加单元的开发、制造和详细测试。测试程序将包括土壤试验室中的受控实验室测试、冲击速度影响的测试以及现场概念验证。

Subaqueous sediment dynamics impact on a large number of issues in the coastal zone and the marine environment, such as coastal erosion and evolution, marine slope stability, navigable water depth, stability of offshore structures, as well as the seafloor as a habitat. One of the unsolved questions with regard to subaqueous sediment dynamics is the thickness, density and particle distribution within the mobile seafloor surface layer. The project aims to develop a mobile seafloor sediment sampler as an add-on unit for portable free-fall penetrometers. The capability of sampling the density, thickness and sedimentological composition of the mobile seabed sediments would pave the way for new studies and insights in the field of subaqueous geomorphology and morphodynamics, sediment dynamics, marine geology, as well as coastal and offshore engineering and seafloor geotechnical engineering. It would contribute directly to the site-specific and systematic understanding of subaqueous sediment transport and scour, and would fill gaps in current knowledge regarding bedload transport. Thus, the resulting instrument will potentially initiate new interdisciplinary collaborations, and address a variety of modern environmental and societal issues. The development will also impact significantly on the career and following research path of the principal investigator whose work is aiming to bridge the gap between subaqueous sediment dynamics and geotechnical engineering. A graduate research assistant working on the development will be educated and trained in detail in sediment transport theories and practice, in-situ marine geotechnics, and coastal and offshore surveying. The fact that a major part of the testing will be conducted on Virginia Tech's campus will allow insight to other students, possibly full classes, and an easy transfer of the gained knowledge and procedures into the class room. Particularly, female students will benefit from the principal investigator as a role model for female researchers in the still male-dominated field of ocean technology and offshore surveying.The mobile seafloor surface layer sampler will be developed as an add-on unit for portable free-fall penetrometers which have been applied for the investigation of sediment mobilization processes for several years. A sampling tube with sealing mechanism will be integrated in the steel tip of the free-fall penetrometer, building a sampling unit that will allow collection of small sediment samples while geotechnical profiling. The project will include the development, manufacture and detailed testing of the add-on unit. Test procedures will feature controlled laboratory tests in a soil test chamber, tests of the effects of impact velocity, and proof-of-concept in the field.