Effect of hydraulic and mechanical characteristics of sediment layers on water film formation in submarine landslides

Progress in Earth and Planetary Science

Keiji Kitajima¹  Shogo Kawakita²  Daisuke Asahina³  Takato Takemura⁴  Hinako Hosono⁴ 

[1] Department of Oceanic Architecture and Engineering, College of Science and Technology, Nihon University, 101-8308, Tokyo, Japan;Department of Oceanic Architecture and Engineering, College of Science and Technology, Nihon University, 101-8308, Tokyo, Japan;Geological Survey of Japan, AIST, Tsukuba, 305-8567, Ibaraki, Japan;Geological Survey of Japan, AIST, Tsukuba, 305-8567, Ibaraki, Japan;Geomechanics Laboratory, Department of Earth and Environmental Sciences, College of Humanities and Sciences, Nihon University, 156-8550, Tokyo, Japan;

关键词: Water film;    Pore pressure;    Submarine landslides;    Layer interface;    Tensile strength;   

DOI  :  10.1186/s40645-020-00375-7

来源: Springer

【 摘 要 】

Through two lab-scale experiments, we investigated the hydraulic and mechanical characteristics of sediment layers during water film formation, induced by elevated pore pressure—considered one of the triggers of submarine landslides. These involved (1) sandbox experiments to prove the effect of water films on mass movement in low slope gradients and (2) experiments to observe the effect of the tensile strength of semi-consolidated sediment layers on water film formation. Portland cement was used to mimic the degree of sediment cementation. We observed a clear relationship between the amount of cement and pore pressure during water film formation; pressure evolution and sediment deformation demonstrated the hydraulic and mechanical characteristics. Based on the results of these experiments, conditions of the sediment layers during water film formation are discussed in terms of pore pressure, permeability, tensile strength, overburden pressure, and tectonic stresses. The results indicate that the tensile strength of the sediment interface provides critical information on the lower limit of the water film formation depth, which is related to the scale of potential submarine landslides.

【 授权许可】

CC BY