Design and Implementation of Integrated Monitoring System for Deep Tunnel Sewerage System Phase 2 (DTSS2) Project in Singapore
Lai Lynn WOO1, Aung Ko Ko SOE1#+, Kyi KHIN1, Simon YIM1, Darryl TAN1, Angus MAXWELL2, Elpidio VALDEZ. JR2
1DTSS2 Department, National Water Agency, PUB, Singapore, 2Maxwell Geosystems, Singapore

Singapore’s DTSS2 project comprises 50 km of tunnelling by 19 Tunnel Boring Machines (TBM) and another 50 km of link sewer pipe jacking work at depths between  35 to 55m below the surface to channel used water to a new centralised water reclamation plant to be constructed in Tuas. Deep tunnelling works inevitably cause disturbance to surrounding ground and the DTSS2 construction in built-up urban environments represents a significant  risk to existing structures. As such, TBMs used on the project are heavily instrumented to achieve better control in operation. Every work activity is designed to be monitored with arrays of geotechnical instruments and other sensing providing data at all times. The data volume is expected to be large and to efficiently manage and utilise these data, Singapore’s National Water Agency, (PUB) devised, procured and implemented an integrated monitoring system known as the Shaft and Tunnel Excavation Monitoring System (STEMS). STEMS is a bespoke web-based data management system configured in accordance with project specifications and requirements. It is designed to streamline continuous progress and production data flows from TBMs, pipe jacking and shaft sinking machines and integrate with various other monitoring data sources, soil investigation data and construction information. After near real time processing, quality engineering data is delivered in a timely manner, with on-the-fly integration tools for analysis and interpretation. In addition to core monitoring features such as data visualization, reporting and automatic alert messaging, the system also computes and presents detailed construction progress and completion status of every shaft excavation and TBM drive. The statistical breakdowns of work activities are also available and therefore data transparency is improved with more reliable delivery and accuracy. Moreover, real-time display of TBM parameters and digitalization of various construction data with centralized storage on a common data server offers instant and convenient access to construction managers, supervision teams and engineers to make fast and correct decisions. The system is proven to be effective for urban tunnelling projects and to positively impact construction efficiencies. This presentation outlines the architecture, functionalities and some key benefits of implementing STEMS in the DTSS2 Project.