Hole through on Moscow cable bore

Lovat's 3.9m diameter mixed face EPBM driving the first phase of a Moscow cable tunnel project between Voikovskaya and Grazhdanskaya holed through last month, and the Canadian firm has similar projects pushing ahead in Russia - plus a rock cable drive soon to commence in Australia.

Local Russian contractor Mostovik achieved average advance rates of 12m-14m per day with the RME152SE Series 21000 machine to excavate the 1,129m long cable tunnel between Voikovskaya and Grazhdanskaya in Moscow.

Geology along the route consisted of sedimentary deposits of mostly fine sand but there were other grades and loam on the drive, which was entirely below the water table. The head of water ranged from 6m-14m above the tunnel invert level.

The cable tunnel market in major cities like Moscow and London is heating up as assets age, power demand rises and infrastructure becomes more congested. Elsewhere in Moscow, therefore, similar jobs are underway.

Lovat is involved in two other cable tunnel projects in the city, one being a 1.8km long tunnel at Gertsevo driven by a 3.3m diameter EPBM through glacio fluvial deposits of mixed sands and loam, similar to the Voikovskaya to Grazhdanskaya tube. The Lovat RME137SE TBM began work earlier this year.

Contractor on the project is local firm Geoton, which has Lovat also providing technical services for coordination, design, procurement, segment design and segment production. The tunnel lining consists of six trapezoidal segments per 1m long, 3m i.d. ring.

Excavation is due to start soon on the other, relatively short cable tunnel in the city - the 682.5m long link from the Babushkin substation to the Moscow electricity grid. Contractor Spetstonnelstroy placed the order with Lovat last December and delivery of the EPBM, which is similar in size to that used on the geoton job, was due this month.

Like on the other drives in the city, the geology along the route consists of saturated sedimentary deposits. On the Babushkin drive, though, the head of water is up to 10m and the cover ranges from 5m-20m.

Far from the busy cable tunnel market of Moscow, Lovat is to supply a refurbished 3.72m diameter single shield rock TBM to contractor Theiss for the City West Cable Tunnel project in Sydney. The TBM is to be shipped towards the end of 2007.

Like in Moscow the entire run of the 1,560m long bore under the Australian city will be below groundwater level, but the head over the invert is higher - up to 24m.

The geological strata along the alignment consists of sandstone interbedded with siltstone, mudstone and shale. Dolerite intrusions are anticipated, too, and fracture zones have been identified.

The 3.9m diameter Lovat EPBM holes through on the Voikovskaya-Grazhdanskaya cable bore, Moscow break 1 The 3.9m diameter Lovat EPBM holes through on the Voikovskaya-Grazhdanskaya cable bore, Moscow break 2 The 3.9m diameter Lovat EPBM holes through on the Voikovskaya-Grazhdanskaya cable bore, Moscow break 3