The two 4.12m-diameter Herrenknecht EPB shield machines working on the project have navigated diverse strata including diorite, granodiorite, gneiss and coral limestone to complete 7.83km of the 14km drive.
Thrustboring Construction Company (TCC) has deployed a dual-heading approach to maximise efficiency from a single central shaft.
TCC says the north TBM has demonstrated exceptional reliability, surpassing 70% completion despite the complex geological formations encountered.
Production of the precast concrete segments – six segments per ring – is also progressing and is now 85% complete.
TCC says using steam-curing technology accelerated the production timeline and having all segments ready on site eliminates any supply chain risks related to the tunnel lining.
The National Water Company’s East Jeddah Sewerage Tunnel is a main sewer line linking East Haramain Road in the south and the outlying airport pumping station 2.
