1. State Key Laboratory for GeoMechanics and Deep Underground Engineering, School of Mechanics and Civil EngineeringChina University of Mining and Technology Xuzhou Jiangsu 221116 China
2. Key Laboratory of Transportation Tunnel EngineeringSouthwest Jiaotong University, Ministry of Education Chengdu 610031 China
3. School of Civil EngineeringUniversity of Leeds Leeds LS2 9JT UK