1 Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000, China; Department 403, Rocket Force University of Engineering, Xi'an 710025, China.
2 Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000, China; College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China.
3 Laboratoire de Physique et Mécanique des Milieux Hétérogènes, École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris, Paris 75005, France; Departamento de Física, Universidade do Ceará, Fortaleza 60020-181, Brazil.
4 Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000, China; College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China. Electronic address: huangn@lzu.edu.cn.