Abstract
A numerical model of the dynamic triaxial test of graded crushed stone was established based on DEM (Discrete Element Method) to study its dynamic characteristics. The influence of test conditions on simulation results was analysed through numerical simulation. A method for determining the test conditions was proposed, and the reliability of the simulation was verified. We studied the accumulation rule and failure standard of permanent deformation. We then determined the critical failure stress level. The prediction model of permanent deformation cumulative failure was then established. When the calculation time step is greater than 1E-4 s per step, the stability of the dynamic triaxial numerical test of graded crushed stone is good. The plastic deformation of the simulated specimen tends to be stable under 10,000 dynamic loading cycles. When the specimen height and diameter are greater than 20 and 10 cm, respectively, the specimen size has little influence on the simulated axial strain. The recommended specimen size is 10 cm (Ф) × 20 cm (h). The action time curve results are consistent with indoor measurement results, which proves the simulation's reliability. The critical failure stress is approximately linearly correlated with the confining pressure, and the cumulative failure equation of plastic deformation is established.
Highlights
Graded crushed stone is often used in road pavement bases
Brown and Chan studied the nonlinear characteristics of graded crushed stone using many laboratory tests and fitted the recommended regression equation and parameter range through a large amount of data [3]
Based on DEM and particle flow theory, the dynamic triaxial numerical test method of graded crushed stone is constructed in this work to study the plastic deformation law and critical failure stress of graded gravel, and the cumulative failure equation of plastic deformation of graded gravel is proposed
Summary
Graded crushed stone is often used in road pavement bases. It is immensely significant to study the dynamic and deformation characteristics of graded crushed stone to improve pavement durability [1]. Rada and Witczak studied the behavior law of plastic deformation and rebound deformation of graded gravel through an indoor dynamic triaxial test [4]. Wang et al studied the development law and distribution state of plastic deformation of graded crushed stone base under long-term vehicle load [7, 8]. To solve the abovementioned problems, the DEM is widely used for studying mechanical properties of road materials, which provides a theoretical basis and method support for the study of dynamic characteristics of graded crushed stone [11,12,13,14,15]. Based on DEM and particle flow theory, the dynamic triaxial numerical test method of graded crushed stone is constructed in this work to study the plastic deformation law and critical failure stress of graded gravel, and the cumulative failure equation of plastic deformation of graded gravel is proposed
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