An Upper Limit Method for Limit Analysis of Jointed Rock Mass Based on Mixed Numerical Discretization

Abstract

The invention relates to a plasticity limit analysis upper-bound method of a non-across jointed rock mass, and belongs to the field of bearing capacity analysis of the rock mass in rock mechanics. The method comprises the steps of: on the basis of an upper-bound method theory in plasticity limit analysis, discretizing a non-across jointed rock slope by adopting a hybrid element method, namely constructing a kinematically admissible velocity field which simultaneously meets block and structural surface deformation compatibility conditions, plasticity flowing constraint conditions, internal and external power equivalence conditions, block element and triangular element interface plasticity flowing conditions and velocity boundary conditions by adopting a rigid block element discretization rock, a finite element discretization rock bridge, a block element centroid speed and a triangular element node velocity as unknown quantities; and building a linear mathematical programming model of solving an ultimate load of the non-across jointed rock mass, solving the linear mathematical programming model by adopting an interior point algorithm and obtaining an upper-bound solution of the ultimate load of the non-across jointed rock mass. The plasticity limit analysis upper-bound method has the characteristics of clear concepts, high calculation accuracy and the like.

Description

technical field [0001] The invention relates to a method for analyzing the upper limit of the plastic limit of a non-penetrating joint rock mass, in particular to an upper limit analysis method based on discrete mixed values, and belongs to the technical field of rock mass bearing capacity analysis in rock mechanics. Background technique [0002] Rock mass is a complex geological body composed of rock blocks and structural planes (joints, fissures, faults, etc.), and the existence of joint planes has a great influence on the bearing capacity of rock mass. Some joints in the rock mass are continuous and some are non-penetrating. The non-penetrating jointed rock mass has the following two important characteristics: First, the penetrating joints cut the rock mass into complex rock block systems, and the failure of the rock block system is mainly due to the The failure of the structural plane between blocks; on the other hand, the non-penetrating joint part has the mechanical ef...

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Problems solved by technology

[0004] (1) If the rigid body limit equilibrium method needs to artificially assume a sliding surface in advance, and then conduct multiple trials to find the most unfavorable sliding surface according to the assumed multiple different sliding surfaces, for the rock mass with a large number of joints, the calculation The amount is large, and it is not easy to obtain the most unfavorable sliding surface;

[0005] (2) Finite element method, discrete element method, etc. have certain difficulties in simulating complex joint networks, complex constitutive relations of jointed rock mass and solving safety factors

However, most of the current domestic and foreign research results in the field of the upper bound method focus on soil slopes, foundations or simple rock slopes, while the research results on non-penetrating joint rock mass Very few, the main reason is that it is difficult to use the principle of limit analysis upper limit method to establish the maneuverable velocity field of non-penetrating jointed rock mass

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