Inner Doha Re-sewerage Implementation Strategy (IDRIS)
The Qatar Public Works Authority (Ashghal) initiated a significant infrastructure programme called the Inner Doha Resewerage Implementation Strategy (IDRIS), with the aim to modernise and improvise the sanitation system in the southern part of Doha, the capital city of Qatar. The project will upgrade the existing sewerage system, which consists of shallow sewers, and numerous pumping stations, through the development of a major deep tunnel sewer network and advanced sewage treatment works.
The main trunk sewer is 45 km in length, with internal diameters between 3 m and 4.5 m and depths between 20 m to 55 m. The first contract, which includes the construction of the three northern segments of the main trunk sewer in central Doha, was awarded to Bouygues Travaux Publics-Urbacon Trading & Contracting WLL and Bessac SAS JV. The tunneling length of this project is approximately 16 km x 3 m diameter with 3 branches (Northern, Eastern & Western branches) including a total of 11 shafts (7 no. Work Shafts & 4 no. Access Shafts).
Bouygues Construction Qatar and UrbaCon Trading and Contracting won the third contract that includes the construction of the southern segment of the main trunk sewer, which will terminate at the new Doha South sewage treatment works. Unfortunately, the project was held due to some issues. The tunneling length of this project was approximately 14 km, including a total of 8 shafts (3 no. Work Shafts & 5 no. Access Shafts).
Encardio-rite’s sister concern, Encardio Rite in Qatar, was entrusted with the monitoring instrumentation works for shafts and tunnels during excavations and TBM drive for civil construction, underpass road tunnel, and underground metro subway stations. Scope of works included:
- Supply & installation of geotechnical instruments and geodetic targets through subcontractors
- Supply, installation & automatic online monitoring of strain gauges through our web-based data monitoring services.
- Supply, installation & automatic online monitoring of optical prisms through our web-based data monitoring services.
- Supply, installation & manual monitoring of crack meters
- Vibration monitoring during TBM drive
- Dilapidation survey (pre- and construction Survey) of all nearby structures, utilities, landscape, and Road infrastructure.
Instrumentation used included:
- Inclinometers were used around shafts to monitor sub-surface lateral movements
- Standpipe piezometers were used to monitor groundwater levels during deep excavations
- Strain gages were used on the lifting beam (slings for a spreader beam) and the TBM thrust frame to measure load and to monitor the stress/strain of several elements of this thrust frame, during the start of the tunnel boring.
- Crack meters were used on subway tunnel walls to monitor existing cracks.
- Optical prism targets were used on retaining walls and columns of underpass to monitor 3D deformation during the passing of TBM and settlement monitoring of the metro underpass.
- Surface settlement points were fixed on surfaces, curbs, pavements, structures, and utilities to monitor vertical movements during construction.
- Vibration sensors were used along the tunnel to check whether the vibration caused by the excavation equipment was within permitted limits.
| Project Details | Inner Doha Re-sewerage Implementation Strategy (IDRIS) |
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| Location | Doha, Qatar |
| Client | Public Works Authority-ASHGHAL |
| Contractor | Bouygues Travaux Publics-Urbacon Trading & Contracting WLL and Bessac SAS JV |
| Project Consultant | CH2M/JACOBS |
| Project Designer | AECOM |
| Year | 2015 - 2017 |