Versatile equipment range, technical site support and continuous product supply in difficult geological conditions
IDRIS MTS-01 was the main trunk sewer line package awarded to Bouygues UCC Bessac JV. The contractors were to complete 14 km of 4.5 m outer diameter main trunk sewer tunnel excavation in the West, North and East branches.
The project involved the excavation of 7 work shafts and 4 access shafts. The Tunnel was driven using an EPB TBM supplied by HK.
The tunnel lining segments comprised HDPE panels integrated into the pre-cast concrete, with each panel welded together at the inner face after tunnel installation.
The shafts ranged in construction methodology from top-down sprayed concrete linings to VSM shafts, prior to membrane installation and final cast concrete linings
The geology of Qatar presented the teams specific challenges that required focused attention. The complex stratum has networks of fissures that enable ground water to freely flow under pressure into open excavations.
Karstic features are found in the organic limestone and the groundwater and high-water table are extremely aggressive.
The contractor needed various products for the different stages of the construction process.
These ranged from the Normet shotcrete pumps, chemicals for the concrete admixture and accelerators for the wet spray concrete method.
Normet also provided TBM specialist soil conditioning foams, breakthrough pre-grouting polyurethane resins, admixtures for rock bolts and micro-fine cements for the VSM shafts and audits.