Dynamic response of the heterogeneous deep-sea sediment with nonlinear gradient modulus to mining machine loading

Abstract

The deep-sea sediments are usually heterogeneous due to overburden pressure. Excessive deformation of deep-sea sediments caused by mining collector vibration can decrease the stability and reduce the efficiency of the mining system. This study analyzed the dynamic response of the heterogeneous deep-sea sediments under mining collector vibration. First, experiments were conducted to confirm the heterogeneity of deep-sea sediments, and to reveal the relationship that the elastic modulus increases nonlinearly with depth. After that, by predigesting the mining collector vibration to in situ harmonic load, the wave equations were built for solving the dynamic response of deep-sea sediments with nonlinear modulus to mining collector loading. The solution of the equations was verified by comparing it with existing analytical solutions for a homogeneous medium. Based on the verified wave equations, further discussion was conducted on the effects of changing vibration frequency or loading amplitude on the mechanical response of deep-sea sediments. The results indicate that the soil deformation was increased but later decreased with the increase of vibration frequency, and soil deformation increased with the increase of loading amplitude. This study can provide a theoretical rationale for improving the walking efficiency of the mining collector.