Optimization of Support System for Tunnel on The Basis of BRT Monitoring Data Samadi Hamid1, Patel Rahul Dev2, Yadav Ajit Singh3, Mishra Eshita4, Khokhar Chander5 1Resident Geotechnical Engineer, RKSH-KNPG Railway Project, AECOM India Pvt Ltd. 2Engineering Geologist, RKSH-KNPG Railway Project, AECOM India Pvt Ltd. 3GGM/Projects, RNVLRishikesh 4Project Engineer, AECOM India Pvt Ltd, Gurugram, Haryana 5Executive Director, AECOM India Pvt Ltd, Gurugram, Haryana Online Published on 28 September, 2023. Abstract Tunnelling in Himalayan geology is overly critical/ challenging due to complex and uncertainties of geological condition. There are just 9 investigation boreholes drilled during tunnel 11-9.5 km-average 1 borehole per each 1 km. The limited number of bore holes will not be sufficient to capture the different geological variations along the complete alignment. Since the initial stretch of this alignment is passing below the city of Srinagar, it was made sure during the design phase to adopt a conservative approach of to cater for any unforeseen or missing information with the limited geological and geotechnical information. During the excavation of escape tunnel, based on face mapping report, technical investigation and BRT monitoring report, optimization of support system will be conducted. Monitoring of ground deformation in tunneling is a principle means for selecting the appropriate excavation and support methods among those foreseen in the design, for ensuring safety during tunnel construction including personal safety and structure located at ground surface and finally, for ensuring construction quality management. The O norm behavior type classification adopted in design phase is little complicated to execute on site because it is more of a qualitative assessment than quantitative like RMR or GSI. The final decision regarding the support type and requirement shall be taken on site after observing the excavated face and actual ground conditions. Support system optimization can be done on site itself by issuing an instruction if convergence values are within the limits and ground conditions are favorable. Monitoring of target point section along the tunnel excavation is simple method to compare with design and actual condition, also will be useful for safety issue. In this paper, an attempt is made to compare BRT monitoring in escape tunnel in poral 1, adit 6 and portal 2 of Tunnel 11 to increase or decrease of rock support system. Top Keywords Rishikesh-Karanprayag railway tunnel project, Optimization of support system, Bi-Reflex target monitoring Data. Top |