1. Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Xiaohongshan, Wuchang, Wuhan 430071, Hubei, China, https://orcid.org/0000-0001-6111-8414 (G.L.)
2. Department of Engineering, Durham University, South Rd., Durham, DH1 3LE, UK (Corresponding author), e-mail: d.g.toll@durham.ac.uk, https://orcid.org/0000-0002-9440-9960
3. Department of Engineering, Durham University, South Rd., Durham, DH1 3LE, UK