On the stress-force-fabric equation in triaxial compressions: Some insights into the triaxial strength |
| |
| Institution: | 1. Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, 1 Xikang Road, Nanjing 210098, China;2. Shanghai MCC13 Construction Corporation Limited, 2469 Tieli Road, Shanghai 201900, China;3. Key Laboratory of Failure Mechanism and Safety Control Techniques of Earth-rock Dam of the Ministry of Water Resources, 223 Guangzhou Road, Nanjing 210029, China;4. School of Computer Science, Engineering and Mathematics, Flinders University, Adelaide, SA 5001, Australia;1. Department of Civil, Environmental and Infrastructure Engineering, Volgenau School of Engineering, George Mason University, Fairfax, VA 22030, USA;2. Stantec Consulting Ltd., 10160 112 St., Edmonton, Alberta T5K 2L6, Canada;1. School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510640, China;2. School of Civil and Construction Engineering, Oregon State University, Corvallis 97333, USA;3. Powerchina Huadong Engineering Corporation Limited, Hangzhou 310014, China |
| |
| Abstract: | The strength of granular materials during triaxial compression is investigated via a grain scale analysis in this paper. A 3D Discrete Element Method (DEM) program provides the triaxial strength data and helps to validate the micromechanical analysis. Some standard methods in statistics are employed first to quantitatively examine the assumptions made when deriving the stress-force-fabric (SFF) equation. After careful validation, a more concise format for the SFF equation is proposed for triaxial compressions. With this SFF equation, the strength is found to be jointly contributed by the magnitudes of the contact force anisotropy and fabric anisotropy. The influence of the initial void ratio, confining pressure and loading direction on the development of contact force anisotropy and fabric anisotropy is examined and presented. With similar techniques, the “force” term in the SFF equation is further decoupled, and an equation is obtained such that it explicitly links the contact force term with the friction coefficient between grains, a tensor defined as a statistic of the normal contact forces and a tensor defined as a statistic of the mobilisation status of contacts. Based on this equation, another equation regarding the stress ratio of granular assembly is obtained, and it clearly indicates two sources that contribute to the phenomenological friction nature of granular assembly. These two sources are caused by the contact force at the grain scale. The first is the anisotropy of the average normal contact forces, and the second is the mobilisation of contacts. |
| |
| Keywords: | Granular materials Triaxial strength DEM Stress-force-fabric equation Contact force anisotropy |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
