Robbins EPB Roars to Life in Azerbaijan

On Aug. 22, 2011, construction of Baku, Azerbaijan’s third metro line got a jump start with the launch of a Robbins EPB. The 6.3 m (20.7 ft) diameter TBM for contractor Azerkorpu is one of two EPB machines excavating parallel 3.5 km (2.2 mi) tunnels approximately 15 m (50 ft) apart.

The capital city Baku is home to 1.7 million people and is known for its chronically clogged city streets. Improved transportation infrastructure is a country-wide initiative in Azerbaijan, where the economy is rapidly growing due to substantial oil reserves. 

“Azerbaijan is poised to become one of the richest countries in the world. There is no doubt that with the increase in economic interest the population will soon outgrow the already outdated and undersized transportation infrastructure,” said Evan Brinkerhoff, Robbins field service superintendent.

So far, the ground has consisted of full-face clay, similar to London blue clay, with no appreciable ground water, pebbles or soil. “The material is sticky, and our initial advance was limited because the pit size was only long enough to muck out with one car. Our machine performance has since improved,” said Brinkerhoff.

As the TBM mines, it is placing 5+1 universal concrete segments using Robbins-supplied segment plant. Muck is being stored in separate storage stations for each TBM, and is then trucked away during the day.

The Robbins machine features a mixed ground cutterhead with carbide bits that are interchangeable with disc cutters depending on the geology. Four independent foam injection points in the cutterhead evenly consolidate the face in the ground conditions. The design results in decreased cutterhead wear and a smooth flow of muck into the mixing chamber.

The new metro Line 3, for owner Metrostroy Azerbaijan, will connect to the existing Line 1 as well as a new bus station. The EPBs are excavating two sections connecting Cavadxan Station and Avtovagzal station sites. Upon completion of the first leg, the machines will continue on to excavate between the Memar Ajami-2 station and an as-yet-unnamed station located near the Azerbaijani Defense Ministry’s hospital. The stations are expected to open in 2013.

This article was submitted by The Robbins Co.

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