Three-Dimensional Discrete Element Model for Tri-axial Tests of Graded Stones Under Different Gradations
In Highway Engineering , graded stones are popularly used in constructing base or subbase layers of pavements. Under cyclic vehicular loads, deformation and strength of graded stones are impacted by various factors. Those factors may include loading magni
- PDF / 396,479 Bytes
- 9 Pages / 439.37 x 666.142 pts Page_size
- 67 Downloads / 152 Views
Abstract In Highway Engineering, graded stones are popularly used in constructing base or subbase layers of pavements. Under cyclic vehicular loads, deformation and strength of graded stones are impacted by various factors. Those factors may include loading magnitudes, aggregate gradations, and particle morphological features. Laboratory tests are used as conversational approaches to predict and characterize performance of the designed graded stones. However, conversational tests are expensive and less efficient. As an alternative approach, a virtual testing method based on the discrete element method (DEM) is lab-independent with the higher efficiency. Additionally, micro-scale or meso-scale features of mixtures may be investigated through virtual tests. Under this background, objectives of this research are to present a three-dimensional discrete element modeling approach for virtual tri-axial tests of graded stones and to improve the fundamental understandings of graded stones’ mechanical behaviors through analyzing the virtual testing results. In the three-dimensional DEM model, aggregate particles are simulated by the spheres in different diameters and given granular parameters to simulate realistic conditions. The cylindrical samples with diameter of 20 cm and height of 40 cm are prepared in this research and the virtual tests are performed with different gradations. Mechanical performance of stress and strain is recorded during the simulation for further analysis. Through this virtual test, the effect of gradation on mechanical properties of coarse aggregate has been presented.
1 Introduction Graded stones have been widely used in base and sub-base. However, these granular materials have obvious particle structure features and nonlinear mechanic characteristics. Many researchers have investigated the influence of structure type to H. Wang B. Ma X. Zhou Y. Liu (&) Highway School of Chang’an University, South Erhuan Middle Section, Xi’an 710064, Shaanxi, China e-mail: [email protected] © Springer Science+Business Media Singapore 2017 X. Li et al. (eds.), Proceedings of the 7th International Conference on Discrete Element Methods, Springer Proceedings in Physics 188, DOI 10.1007/978-981-10-1926-5_96
917
918
H. Wang et al.
mechanical properties through tri-axial tests. Because in tri-axial tests, principal stress, loading path and style, and specimen size could be controlled [1, 2]. Previous research presented a numerical method to investigate how maximum particles impacted on model parameters and max density curve theory [3]. In railway engineering, graded stone is normally called ballast, which particles and sample sizes are larger. Many researches results about ballast tri-axial tests revealed that different confining pressure, loading style and frequency had an important impact on resilient modulus of graded stones [4, 5]. However, laboratory tests are expensive and less efficient if one wants to conduct large amount of tests. As an alternative, virtual tests based on discrete element method (DEM) can s
Data Loading...
