A Lower Limit Method for Plastic Limit Analysis of Ultimate Bearing Capacity of Rock Slopes with Rock Bridges

Abstract

The invention relates to a calculation method for ultimate bearing capacities of rock slopes with rock bridges, and belongs to the field of rock slope stability analysis. The method comprises the following steps of: dispersing a rock slope with rock bridges by adoption of a composite element method on the basis of a theory of the plastic ultimate analysis lower limit method; establishing a nonlinear mathematic programming model for stability analysis of rock slopes with rock bridges by taking an ultimate load and a strength reserve coefficient of the rock slope as target functions; and solving maximum values of the ultimate load and the strength reserve coefficient by using a mathematic programming optimization algorithm. According to the method provided by the invention, the plastic ultimate analysis lower limit method, a composite element method dispersion technology and a mathematic programming measure are combined to establish a rock slope ultimate bearing capacity solution method which not only can simulate the continuous media characteristics of the rock bridges, but also can simulate the non-continuous media characteristics of rock blocks. The method provided by the invention has the characteristics of being clear in concept and high in calculation precision, and can be applied to the analysis of bearing capacities of the rock bridges in rock slopes.

Description

Technical field [0001] The invention relates to a method for calculating the ultimate bearing capacity of a rock slope with a rock bridge, in particular to a plastic limit analysis lower limit method based on a composite element method, and belongs to the technical field of rock slope stability analysis. Background technique [0002] A large number of rock slope engineering problems are bound to be encountered in important projects such as mining, transportation, water conservancy and hydropower, and national defense construction. Rock slopes often experience geological disasters such as instability and destruction. For example, in the Wenchuan earthquake, according to statistics from the Ministry of Land and Resources, there were more than 1,800 unstable slope collapses in the entire earthquake-damaged area. These disasters seriously affected the people’s lives and property safety and the sustained and stable development of the national economy. . Therefore, it is urgent to car...

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Problems solved by technology

[0005] (1) Among the mainstream methods for rock slope stability analysis at this stage: although the limit equilibrium method has been greatly improved and enhanced by the efforts of many scholars, it is still only applicable to the upper rock of a single fracture surface or joint cutting surface. The stability analysis of the block, that is, the limit equilibrium method has a certain gap between the assumption of the rock mass and the actual situation, and its application is greatly restricted; the discrete element method and the finite difference method can simulate the interaction between the rock mass and the rock bridge, but in The complex constitutive relationship of the simulated rock mass and the complex joint network are limited, so that the calculation results are affected to a certain extent, and the stability safety factor cannot be directly obtained

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