A Comprehensive Analysis for Impact of Rock Strength Parameters on Face Excavation Patterns and Stability in Himalayan Tunnels

Material characteristics, particularly Young's Modulus and Poisson's Ratio, critically influences the stability of tunnel faces and the accompanying excavation patterns. High Young's Modulus rocks can withstand vertical load, whereas low Poisson's Ratio rocks are less likely to distort laterally. In that case, controlled blasting techniques might be required to prevent excessive fracture and damage to the surrounding rock. The study uses advanced numerical simulations with three-dimensional computational analysis through the use of Midas Gts Nx to examine the behaviour of stress-strain deformation and crown displacement during tunnelling activities. Through a thorough examination of a range of material attributes from real project site of Rishikesh-Karanprayag BG rail tunnel, Uttarakhand, India. The primary objective of the study is to determine the effect of rock strength parameter that have on tunnel face stability and the related tunnel excavation pattern. The results of the study indicate that the Himalayan rock characterizes the optimal excavation scenario with ring cut followed by side drift excavation pattern for face stability. The results of this work provide an improved understanding of the relationship between material qualities and excavation-induced stresses, which has important implications for tunnelling engineering methods. In order to optimize face stability, minimize deformations, and decrease crown displacement, excavation patterns can be customized. This will ultimately lead to safer and more effective tunnelling operations. This research provides the groundwork for well-informed tunnel design and construction decisions, with potential applicability across a range of geological environments and project dimensions.