Quasi-static method for calculating dynamic safety coefficient of homogeneous slope under action of earthquake

Abstract

The invention provides a quasi-static method for calculating a dynamic safety coefficient of a homogeneous slope under the action of an earthquake, which is characterized by comprising the following steps of: reducing strength parameters (cohesive force and an internal friction angle) to obtain reduced strength parameters; deducing two groups of characteristic line differential equations of the slip line field by using a characteristic line method according to the earthquake action stress balance equation set and the Moore Coulomb criterion stress expression, and solving the differential equations by using a finite difference method according to the dynamic boundary conditions of active, transition and passive regions under the earthquake action; obtaining a slip line field under the earthquake action and a slope surface curve (power limit slope surface curve for short) under the power limit state; different dynamic limit slope curves can be obtained through calculation according to different reduction strength parameters, the dynamic stability of the slope under the earthquake action is judged according to the positive and negative of the horizontal coordinate of the intersection point of the dynamic limit slope curves and the slope bottom, when the horizontal coordinate of the intersection point is zero, the slope is judged to be in a dynamic limit state, and the reduction coefficient is the dynamic safety coefficient at the moment.

Description

technical field [0001] The invention belongs to the field of slope stability evaluation, in particular to a quasi-static method for calculating the dynamic safety factor of a homogeneous slope under earthquake action. Background technique [0002] my country is an earthquake-prone country, especially in mountainous and hilly areas. Landslides caused by earthquakes often have the characteristics of wide distribution, large numbers, and great harm. Therefore, the stability of slopes under seismic loads has always Research difficulties and hotspots in the field of earthquake engineering. The quasi-static method is simple in calculation and strong in practicability, and has been included in the corresponding codes for slope dynamic stability analysis. The essence of the quasi-static method is to regard the seismic inertia force as a static load and apply it to the slope body, and then use the limit equilibrium slice method or the strength reduction finite element method to calcu...

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Problems solved by technology

[0003] When using the quasi-static method of limit equilibrium striping, there are two main problems: one is that when the quasi-static slicing method is used to divide soil strips on slope rock and soil, different slicing directions will cause errors in the quasi-static method. Even unreasonable results are obtained; the other is that it is necessary to assume or search for the form of the critical sliding surface, and the calculation formula of the dynamic safety factor considering the seismic inertial force will have a large gap in the results obtained for different critical sliding surface forms, which is not conducive to engineering practice application

The complexity of the numerical calculation model of the seismic inertial force slope and the existence of nonlinear problems will lead to non-convergence of the calculation, and there is no uniform standard for the selection of the position of the characteristic point of the displacement mutation. There will be subjective factors in the point, and the penetration of the plastic zone is a necessary but not sufficient condition for slope failure

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