Numerical study and field performance of rockbolt support schemes in TBM-excavated coal mine roadways: A case study

• Published in: Tunnelling and underground space technology 2021-09, Vol.115, p.104053, Article 104053
• Main Authors: Tang, Bin, Yeboah, Mathias, Cheng, Hua, Tang, Yongzhi, Yao, Zhishu, Wang, Chuanbing, Rong, Chuanxin, Wang, Zhenhua, Liu, Quansheng
• Format: Article
• Language: English
• Subjects: Boring machines; Coal; Coal mine; Coal mines; Coal mining; Discrete element method; Excavation; In-situ monitoring; Mechanical properties; Monitoring; Numerical models; Parameters; Roads; Roadway support; Rock masses; Rockbolt; Rocks; Simulation; Tunnel boring machine; Tunneling; Tunnels; Underground construction; Underground mines
• ISSN: 0886-7798; 1878-4364
• DOI: 10.1016/j.tust.2021.104053

•Deep-buried TBM-excavated coal mine roadways were supported by rockbolts.•Support schemes of installing inclined and perpendicular rockbolts were compared.•Stress concentration and damage of surrounding rocks were quantitatively analyzed.•Loads applied on rockbolts were monitored by self-developed instrumented rockbolts. There is an increasing number of TBMs applied in coal mine roadway excavation projects due to the higher safety, faster tunnelling speed and fewer labor works. Nevertheless, the experiences gained from TBM tunnelling projects of transportation or water conveyance tunnels are not well applicable in underground coal mines because of their special engineering and geological conditions. This paper proposed a case study of the excavation disturbance behaviors and support design of TBM-excavated roadway in Zhangji coal mine in Anhui Province, China. Mechanical properties of roadway surrounding rocks were obtained based on parameters of intact rocks and Rock Quality Designation (RQD) values of rock masses. The Universal Discrete Element Code (UDEC) software was used to establish numerical model of the roadway and micro-parameters are also calibrated. The excavation disturbance behaviors of unsupported roadway were firstly simulated. Moreover, the excavation disturbance behaviors and rockbolts loading characters under two different support schemes were studied and compared based on simulation and monitoring results. In this case, simulation results are in good agreement with monitoring results. Research results and experiences obtained from the working site suggest that installing rockbolts perpendicularly to rock surface can better satisfy the requirements of TBM tunnelling in weak grounds of coal mine roadways.