Catastrophic failure of submarine slopes with elastic shearing zones

Abstract

Submarine landslides can be devastating to offshore facilities and coastal areas. This study explores the triggering mechanisms of catastrophic failure of an infinite planar slope in sensitive soil deposits under undrained conditions. The strain-softening behaviour of sensitive soils can cause rapid growth of the shear band along a thin layer of weak materials and ultimately lead to a large landslide. A new analytical criterion for catastrophic shear band propagation taking into account elastic shear deformation in the shear band was derived using a process zone approach. A mechanical analysis was conducted on the fully softened zone, end zone and elastic shearing zone, among which the evolution of the shear band and the development of key mechanical variables were presented to illustrate the formation mechanism of the large submarine planar landslides. The influences of the elastic properties of soils on the initiation of catastrophic failure were investigated for both clay and sand slopes, demonstrating that the consideration of the elastic properties result in a more conservative failure criterion compared with that presented in the previous study.

Keywords:

• Submarine landslides
• shear band
• strain softening
• undrained shear strength
• elastic shear deformation

Acknowledgment

The authors are grateful for the support of the National Natural Science Foundation of China (No. 51678523).

Disclosure statement

No potential conflicts of interest are reported by the authors.