Discrete element simulation method for rock-soil triaxial test flexible film boundary

Abstract

The invention discloses a discrete element simulation method for a rock-soil triaxial test flexible film boundary. The discrete element simulation method adopts a particle set arranged in a hexagonalhoneycomb structure to represent a flexible film, and a linear bonding model is adopted among particles, and an upper loading plate and a lower loading plate adopt rigid walls. The discrete element simulation method has the outstanding advantages that (1) the film particles can effectively represent parameters such as the elasticity modulus, the Poisson's ratio and the thickness of the physical film; (2) the film can be freely deformed in the sample loading process, and the hydrostatic confining pressure can be stably and accurately transmitted; and (3) the volume deformation of the sample canbe accurately recorded in real time in the loading process. The discrete element simulation method is simple in implementation process and suitable for simulating conventional triaxial tests of various granular materials such as sandy soil and rockfill materials. Practice shows that the discrete element simulation method can accurately simulate the shape change, the stress-strain relationship andthe volume strain condition of the sample in the triaxial test process of the granular material, and can provide powerful support for macroscopic parameter test and mechanical property research of the granular material.

Description

technical field [0001] The invention belongs to the field of geotechnical engineering, and in particular relates to a discrete element simulation method for the boundary of a flexible film in a geotechnical triaxial test. Background technique [0002] Triaxial testing is one of the most important laboratory tests in the field of geotechnical engineering. In engineering, triaxial test is widely used to test the strength and deformation parameters of rock and soil mass, providing parameter basis for design and construction; in scientific research, triaxial test is the main equipment for studying various mechanical characteristics of soil mass. [0003] Because sand, rockfill and other geotechnical materials have natural granular characteristics, the discrete element algorithm with particles as the basic unit is widely used in the research of various geotechnical engineering problems. However, since the mesoscale parameters adopted by the discrete element algorithm are not eas...

AI Technical Summary

Problems solved by technology

However, there are obvious deficiencies in the simulation method provided by this patent: 1) It is impossible to simulate the influence of different film material parameters (such as thickness, elastic modulus and Poisson's ratio, etc.) in the triaxial; However, the parameters involved in discrete element calculations are all mesoscopic parameters such as particle stiffness. How to assign macroscopic parameters such as elastic modulus and Poisson’s ratio to cluster elements calculated with mesoscopic parameters is difficult. realistic technical difficulties

2) Reasonably capturing the volume deformation during triaxial loading is the key to successfully analyzing the deformation behavior of rock and soil. However, this model cannot calculate and reasonably characterize the volume deformation during triaxial loading; 3) Cluster elements are used as the upper and lower For the simulation element of the loaded roof, due to the high stiffness of the upper and lower loaded roofs, the cluster element must adopt a higher stiffness to simulate the rigid loading plate reasonably. However, in the explicit discrete element algorithm, a larger stiffness has to be used in a smaller time The step size is used to ensure the stability of the model calculation. This scheme has low calculation efficiency in specific implementation.

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