NDRC Micro-tunneling work for DEWA 132 kV cable laying
The project works included Horizontal Directional Drilling (HDD) for installation of electrical cables. The tunneling was to be done underneath the existing Sheikh Zayed Road road and Emirates Tower (Red Line) Metro piers. Project included testing and commissioning of 132 kV cable laying works and associated works for 132/11 kV substation.
The horizontal directional drilling technique needed construction of launching and receiving shafts at both ends. The shafts required excavation up to 6 m depth below ground level.
As the project required the construction/excavation works of shaft just adjacent to Red Line Metro piers and tunneling across Sheikh Zayed Road and metro pier, instrumentation was planned for safety monitoring of structures, as well as for the risk management of construction works.
Encardio-rite’s sister concern Encardio-rite Geosystems LLC in UAE was instructed by the Road and Transport Authority (RTA-Owner of Metro structure) and Riyadh Cable Group Company to provide instrumentation and monitoring programs during NDRC to assess the impact on adjacent structures including the Dubai Red Line Metro pier and existing road, as per M/s RTA code of practice. Scope of works included:
- Pre-construction building condition survey of metro piers and its viaduct.
- Supply of geotechnical instruments, precise survey instruments
- Installation of geotechnical instruments including subsurface instruments
- Manual and automatic monitoring
- Precise leveling
- Setting up an online web-based data management system (WDMS) and maintenance during the contract period
- Daily & weekly reporting with evaluation & interpretation
Instrumentation included:
- Instruments for Metro Pier monitoring
- Automatic Vibration sensor Installed on metro piers to monitor any vibration caused by nearby construction works
- Building settlement points Installed on metro piers to monitor any settlement caused by nearby construction works
Instruments for surface/sub-surface monitoring near construction works
- Borehole extensometer Installed to monitor subsurface settlement in the ground around metro pier, during tunneling.
- Surface settlement points Installed in the soil to monitor surface settlement along the tunnel alignment as well as near the metro pier
Installation and monitoring of the above-mentioned instruments were executed successfully by experienced and proficient I&M team of Encardio-rite.