1. Cavarretta I, Rocchi I, Coop MR (2011) A new interparticle friction apparatus for granular materials. Can Geotech J 48(12):1829–1840
2. Chuai J, Wang L-M et al (2017) Validation and analysis of calibration method for micro parameters of wheat PFC model. China Powder Sci Technol 23(04):43–48
3. Clayton CRI (2011) Stiffness at small strain: research and practice. Géotechnique 61(01):5–37
4. Itasca Consulting Group Inc. (2008) Manual of particle flow code in three dimensions (PFC3D), version 4.0. Itasca Consulting Group, Inc., Minneapolis, MN
5. Ji M-X, Chen Y-M, Huang B (2003) Method for precisely determining shear wave velocity of soil from bender element tests. Chin J Geotech Eng 06:732–736