Expolink Route 2020 Dubai Metro, UAE Project
The Expolink Route 2020 Metro Rail Project extends the existing Dubai Metro Red Line. It consists of a branch line starting at Nakheel Harbour and Tower Station and extending to the 2020 Expo site. The alignment for the project includes approximately 2 km of bored tunnel excavated by tunnel boring machines (TBM) and 10 km of elevated structures.
A comprehensive instrumentation and monitoring program was undertaken before, during, and after the Route 2020 Metro Rail Project (underground) construction.
Project Details
| Project | Location | Client | Contractor | Consultant | Designer | Duration |
|---|
| Expolink Route 2020 Dubai Metro Rail Project | Dubai, UAE | Roads & Transport Authority | Expolink-CWJV | Parson-Systra JV | CH2M | 2017-2020 |
Why Monitoring?
The instrumentation and monitoring process aimed to determine ground movements and accurately evaluate the effect of the construction works on nearby structures, services, and utilities. This was done to allow direct comparison with performance criteria and design expectations. The instrumentation data helped systematically identify significant design risks systematically and prioritize actions to minimize and manage construction risks. This provided information to evaluate structural stability and the possibility of implementing corrective measures if necessary.
Monitoring Solution
Encardio-rite Geosystems, UAE, monitored the construction activity at the Expolink Route 2020 Metro Rail Project before, during, and after. The purpose of the monitoring work, using geotechnical instrumentation, included:
- Safety of building & utilities
- Design Verification
- Construction Control
Instrumented sections included underground stations, annex structures, cut-and-cover deep excavations, tunnel alignment, the NDRC Line, buildings and utilities within the zone of influence of excavations and tunneling works, and existing metro piers.
Turnkey Services Provided
- Conducting They installedThere are two pre-condition surveys of construction sites (photographic record & reporting)
- Establishment, maintenance, and measurements of the survey network
- Supply, installation, and monitoring of geotechnical instruments to monitor the response of underground structures (stations, excavation & retaining walls)
- Setting up an online web-based data management system (WDMS) and maintenance during the contract period
- Weekly & monthly reporting with evaluation & Interpretation
- Manual and automatic monitoring
Instruments Used
| Instrument | Purpose |
|---|
| Standpipe Piezometer | Installed outside excavation areas to determine groundwater behavior before, during, and after construction activities. |
| Inclinometer | Installed outside excavation areas and within the diaphragm wall to determine lateral deformation of ground and D-wall due to excavation activities. |
| In-Place Inclinometer | Installed in diaphragm wall, used to measure lateral deformation. |
| Automatic Groundwater Recorder | Used to measure groundwater level at every one-hour interval during the excavation period. |
| Extensometers | Installed adjacent to station box excavations to measure settlement at depths. |
| Surface Settlement Points | There are two types: hard pavement & soil. Used to determine ground surface deformation. |
| Prism Target | Used for 3D measurement of deformation during building construction. |
| Strain Gauges | It measures the strain developed on the strut support through ESDL dataloggers and also measures strain while cutting rail tracks for the metro route extension. |
| Robotic Total Station | Automatic surveying using total stations and an in-house developed control box for deformation monitoring. |
| Dataloggers | Used to collect data automatically from sensors installed at critical locations at required intervals, with wireless transmission to the central server. |
Monitoring Execution
Encardio-rite was responsible for ensuring that all survey investigations were planned and executed safely, complying with all relevant regulations to avoid causing danger, inconvenience, or interference to the general public or other contractors working on site.
During the project execution, all deliverables were subject to an interdisciplinary check before issuance (such as tunnel design, geological/geotechnical, and structural disciplines). All site conditions that might affect the results were recorded with sensor data, including temperature, excavation level, distance of TBM head from the point/excavation level, dewatering, ground improvement, and any other works near the instrument location. This helped in interpreting and evaluating the data, especially in case of any variation in the sensor data.
The automatic and manual monitoring data was available to the Contractor, Client, and Consultant in the form of daily, weekly, and monthly monitoring reports. These reports included interpretations of variations observed in instrument data with respect to the construction progress in the respective areas. Instant alerts were provided for corrective/preventive measures to be taken in time.