The 18km long third section of the 35.75km long Qumrud water conveyance tunnel in Iran (T&TI February 2004) has been making good progress since SELI launched its 4.5m diameter Wirth TBM earlier this year – with up to 39.4m being claimed as the maximum daily advance.
There are three local contractors working independently on the Qumrud works: Peymab Company for the first 9km of tunnel, Stratous Company for the second 9km stretch and Qurb-e-qaeem Company for the last 17.75km. SELI is the sub-contractor for tunnelling on the Qurb-e-qaeem section.
Budgeted at US$89.6M for the base contract prices, the tenders are adjusted annually according to the official inflation rate. The Iranian government financed the scheme from its national budget.
The scheme is intended to improve the water supply between the cities of Qom, Arak and Esfahan by enlarging the water supply’s catchment area with conveyance from the river Dez tributaries.
With an internal diameter of 3.6m the tunnel passes through andesite, limestone, dolomite limestone, schist and shale as well as recent and compacted alluvium. There are also four adits, positioned at chainages 3.6km, 7.1km, 11.5km and 15.8km. The adits are 640m, 1402m, 1690m and 1790m long respectively.
When T&TI contacted the team in August, progress was reported on all three sections and the TBM advance for SELI’s section.
In the first US$19.8M section, 921m on main tunnel had been driven, plus 134m and 703m of the first and second adits. In the US$25.6M second section, both adits were excavated, but no progress had been made on the main tunnel works. For the third section, budgeted at US$44.2M, the TBM and backup were shipped in August 2003 and installation ran from December 2003 to February this year.
As described above, the TBM and crews now seem to be settling into their task admirably.
Amir Farajiazad, a senior manager for Mahab Ghodss Consulting Engineers, which is assisting in project management of the scheme said: “average daily progress is 20m, which could not have been achieved without the backing of Wirth, the manufacturer of the double shield TBM”
