ROCK MASS DEFORMATION AND TBM PERFORMANCE FOR A RAILWAY TUNNEL

Abstract

Tunnel Boring Machines (TBM) operating in jointed rock masses face significant challenges due to the variability in geological conditions. Accurate performance prediction models are essential for optimizing penetration rates and ensuring project efficiency. This study evaluates and compares three TBM performance prediction models: the NTNU model by Bruland (2000), the model by Hassanpour et al. (2011), and the model by Farrokh et al. (2012). A comprehensive site visit was conducted at Devprayag, India, where extensive data on machine performance and geological parameters were collected. These data include rock mass properties, joint characteristics, and TBM operational metrics. The study inputs these parameters into the three models to predict penetration rates and assess their predictive accuracy. The findings highlight the strengths and limitations of each model, providing insights into their applicability under various geological conditions encountered at the Devprayag site. This comparative analysis serves as a valuable resource for engineers in selecting and refining TBM performance prediction models for jointed rock mass environments. Additionally, the squeezing potential of the ground at the Devprayag site was evaluated by calculating tunnel closure and displacement using data from 15 distinct sections analyzed with Rocscience software. This analysis allows engineers to forecast rock mass response to stress and identify areas prone to significant deformation. Understanding these dynamics enables the implementation of effective mitigation techniques to ensure the stability and safety of the excavation process.