Seafloor instability evaluation method

Abstract

The invention relates to a seafloor instability evaluation method. The method comprises: firstly, selecting out critical geological factors influencing seafloor slope stability according to geological environment conditions of seafloor slope occurrence and basic conditions of seafloor slope instability; secondly, selecting out critical induction factors influencing seafloor slope stability through a decomposition mode and a decomposition effect of natural gas hydrates, and constructing a seafloor slope stability influence factor index system; thirdly, constructing a seafloor slope geomechanics model by generalizing the seafloor slope stability influence factor index system; and finally, based on a Mohr-Coulomb failure criterion, proposing a mathematic method for evaluating seafloor slope stability, i.e., an improved finite element strength reduction method, and analyzing an evolutional process of seafloor slope stability and seafloor slope instability induced by decomposition of natural gas hydrates. The method is scientific in principle, high in calculation precision and short in calculation time, considers the induction factors of seafloor slope instability caused by decomposition of natural gas hydrates for the first time, gives out a deformation process of slope instability in combination with the geomechanics model and the finite element numerical analysis method, and has important practical application values.

Description

technical field [0001] The invention belongs to the technical field of marine geological disaster evaluation, and relates to an evaluation method for seabed instability, which is a quantitative evaluation method for evaluating the instability of seabed slopes induced by natural gas hydrate decomposition in seabed sediments. Background technique [0002] The decomposition of gas hydrates is considered to be one of the causes of seafloor slides in many continental margins around the world. Theoretical analysis shows that the decomposition of natural gas hydrate increases the gas content in sediment pores, generates excessive pore pressure, and reduces the cementation strength of sediments. If the slope of the hydrate-containing sediment layer is large, and the hydrate decomposition is more significant, the shear strength and bearing capacity of the sediment layer will be reduced, resulting in instability such as submarine slope sliding. [0003] At present, the research on se...

AI Technical Summary

Problems solved by technology

However, this method largely depends on the understanding of the shape and soil properties of the potential landslide, and cannot solve the influence of many factors such as excess pore water pressure, slope deformation, dynamic response and complex terrain, and cannot simulate the failure of the slope. stable process, there are limitations in application

Images