Quasi-static method for calculating homogeneous slope dynamic limit load under earthquake action

Abstract

The invention provides a quasi-static method for calculating dynamic limit load of a homogeneous slope under earthquake action, which is characterized by comprising the following steps of: firstly, setting a slope crest load change value; then, according to the earthquake action stress balance equation set and the Moore Coulomb criterion stress expression, a characteristic line method is applied to derive two groups of characteristic line differential equation sets of the slip line field, According to the dynamic boundary conditions of active, transition and passive areas under the earthquake action, a finite difference method is adopted to solve the differential equation sets; 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; finally, different dynamic limit loads can be calculated according to different slope top load change values and correspond to different dynamic limit slope curves, the slope dynamic stability under the earthquake action is judged according to plus or minus of the horizontal ordinate of the intersection point of the dynamic limit slope curves and the slope bottom, and when the horizontal ordinate of the intersection point is zero, the slope is judged to be in a dynamic limit state. Wherein the dynamic load calculated by the slope crest load value is a dynamic limit load value.

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 limit load of a homogeneous slope under earthquake action. Background technique [0002] Due to the rapid development of our country's economy, a large number of civil engineering projects have been built. Many abutments, buildings and retaining wall strip foundations are built on the slope, and the top load is formed on the top of the slope, and our country is also an earthquake-prone country. Therefore, the determination of the dynamic limit load of the slope under earthquake is a very important issue. [0003] At present, there are three main methods for determining the dynamic limit load of slopes: (1) The limit equilibrium slice method based on the concept of quasi-static force. This method needs to assume different sliding surface forms, and consider the dynamic safety factor of seismic inertia force corresponding t...

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Problems solved by technology

[0003] At present, there are three main methods for determining the dynamic limit load of slopes: (1) The limit equilibrium slice method based on the concept of quasi-static force. This method needs to assume different sliding surface forms, and consider the dynamic safety factor of seismic inertia force corresponding to different sliding surface forms. There will be a large gap in the calculation results, which is not conducive to the application of engineering practice; (2) the limit analysis method based on the concept of quasi-static force, which also needs to assume the failure mechanism; (3) the finite element or finite difference based on the concept of strength reduction, etc. Numerical analysis method, this kind of method does not need to assume or search for the critical sliding surface, but the determination of the dynamic instability criterion, that is, how to determine that the slope is in the dynamic limit state is a difficult problem. At present, there are three main methods for the slope dynamic instability criterion , including calculation non-convergence criterion, displacement mutation criterion and plastic zone penetration criterion. Due to the complexity of the numerical calculation model of seismic inertia force slope, there are many factors affecting calculation non-convergence, and the disadvantage of displacement mutation criterion is There is no uniform standard for the selection of the position of the feature point. Sometimes the inflection point of the displacement curve of the feature point is not obvious. There will be subjective factors when judging the mutation point artificially. The penetration of the plastic zone is a necessary but not sufficient condition for slope failure.

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