A novel technique for seabed strata deformation in situ monitoring

Seafloor strata deformation monitoring is important for gas hydrate exploitation and the monitoring and early warning of seabed instabilities. Due to the limitation of in situ monitoring technology, existing observations are carried out with geophysical methods to provide basic geomorphological characteristics and stratigraphic structures. However, it is of equal importance to study the in situ evolution mechanism of the process of strata deformation, which relies heavily on long-term in situ observations. An in situ monitoring instrument for seabed strata deformation monitoring is presented. Sufficient theoretical, numerical, and experimental studies were carried out to conduct a mechanical analysis on the entire deployment process of the instrument. The maximum penetration resistance and reaming pressure were calculated during the deployment process, and the stability and feasibility of the deployment method were verified. To validate the maximum penetration resistance obtained and the monitoring performance of the instrument, field tests were conducted on a tidal flat in Changzhi Island. The penetration resistance of the instrument and the strata deformation of the tidal flat were measured and obtained. The results demonstrate the feasibility of the presented instrument.