[ Wang, Dongyuan ; Gao, Bo ] School of Civil Engineering, Southwest Jiaotong University, Chengdu;[ Wang, Dongyuan ; Gao, Bo ] 610031, China;[Zhao, Guobin ] Huadong Engineering Corporation Ltd., Hangzhou;[Zhao, Guobin ] 310014, China;[ Wang, Sijing ] Key Laboratory of Engineering Geomechanics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing
Rock burst is a geological hazard that occurs when hard and brittle rock mass is excavated under high in situ geo-stress or in the presence of high-stress concentration. This paper presents a case study of rock bursts that occurred in the Qirehataer Diversion Tunnel excavation project in gneissic granite. The tunnel is 15.66 km long at a maximum depth of 1720 m below the ground surface, many rock bursts occurred over the total length of 4071.5 m. Detailed geological settings, in situ and laboratory test data, as well as the method that is used to inter-pret the test data to obtain the threshold parameters used for classification criteria, are introduced. A database consisting of 29 rock bursts and classifications using the three criteria is compiled. Based on the database, the criteria are modified to obtain consistent classifications. Evaluation of the modifications and application of the modified criteria to rock bursts in a case study indicate that theconsistency of classifications is greatly enhanced. (C) 2016 Elsevier B.V. All rights reserved.
[Li, XY] Southwest Jiaotong Univ, State Key Lab Tract Power, Chengdu 610031, Sichuan, Peoples R China.
Timoshenko beam;Forced vibration;Transition parameter;Green's function;Equivalent model
The present paper studies the steady-state dynamical problem of an axially forced Timoshenko beam with various boundary conditions, in a systematic manner. In view of the contribution of the axial force to the shear force, the equation of motion available in the literature is expressed in a unified manner, by introducing an intrinsic transition parameter. Methods of separation of variable and the Laplace transform are sequentially employed to find Green's functions. The transverse displacement and the rotation angle of the beam cross section are analytically obtained in terms of elementary functions. The axially loaded Timoshenko beam can be equivalent to a traditional one without axial force. Numerical calculations are systematically carried out to fulfill multiple purposes, including validity of the present solutions, the effect of transition parameter, the influence of height-to-length along with the impact of axial force. (C) 2016 Elsevier Ltd. All rights reserved.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY,2018年77:295-304 ISSN：0886-7798
[Xin, C. L.] Department of Underground Engineering, Taiyuan University of Technology, Taiyuan, China;[Wang, Z. Z.] School of Civil Engineering, Dalian University of Technology, Dalian, China;[Gao, B.] Key Laboratory of Transportation Tunnel Engineering of Ministry of Education, Southwest Jiaotong University, Chengdu, China