Data-driven Site Supervision on Micro Tunnel Boring Machine (MTBM) on Hard Rock Performance - Objective, Analysis and a Case of Effluent Pipeline in a Caverns Project

The Relocation of Shatin Sewage Treatment Works (STSTW) to Caverns involves the construction of twin effluent pipelines for conveying treated effluent to the existing inlet chamber via the Tolo Harbour Effluent Export Scheme (THEES) Tunnel. The paper emphasizes lessons learned from past projects with MTBM jamming underground, leading to project delays, increased costs, safety concerns, and social impacts. This specific case study focuses on a twin pipe driving through a rock mountain. The catastrophic nature of such jamming problem embarks meticulous site supervision, with a 100% successful breakthrough of the MTBM as a paramount objective. Traditional rescue methods, such as vertical shafts, may be impractical and infeasible in our case, further highlighting the importance of comprehensive site supervision by Resident Site Supervisor (RSS). The first part of the paper delves into a detailed case study of one of the twin pipes, and its performance with insights. The second part explores the fundamental aspects of profound site supervision, discussing the rationale for employing site data to achieve project objectives with aims to mitigating the escalating risks associated with MTBM failures. Moreover, it lays the groundwork for further analysis and utilization of operational data for the second effluent pipeline and tunneling industry.