[1] Guizhou Univ, Coll Civil Engn, Guizhou Prov Key Lab Rock & Soil Mech & Engn Safet, Guiyang 550025, Peoples R China
[2] Chongqing Res Inst China Coal Technol & Engn Grp C, State Key Lab Gas Disaster Detecting, Chongqing 400037, Peoples R China
[3] Kingston Univ London, Sch Comp Sci & Math, London KT1 2EE, England
[4] Univ Hertfordshire, Sch Phys Engn & Comp Sci, Hatfield AL10 9AB, England