NEW APPROACH OF THE ESTIMATION OF RHEOLOGIAL PROPERTIES OF SEAFLOOR SEDIMENTS DURING SAMPLING PROCESS
The paper is devoted to the problem of the possibility to study rheological properties of seafloor sediments during sampling process with usage of tube samplers. The problem of sampling tube penetration through soil with complicated visco-elasto-plastic rheology is considered. Estimation of mechanical properties of this medium is among the most important problems emerging during hydrocarbon fields located at Arctic shelf exploration. The proper evaluation of infrastructure objects reaction to external effects (earthquakes, large waves) is needed to reduce the risks of serious accidents at shelf. The paper presents a new approach to determine parameters governing infrastructure stability: static elastic moduli of seafloor sediments, their plastic and viscous properties. Dynamics of tube sampler penetration – measurable dependency of tube acceleration – acts as the source of information regarding these parameters. The inverse problem of reconstructing mechanical properties of seafloor sediments from the characteristics of this dependency is being solved. The paper presents the results of solving the corresponding direct problem with the use of finite element method. The possibility to estimate mechanical properties of seafloor sediments from data on such parameters as time passed until the complete stop of tube sampler and depth of its penetration is demonstrated.