Bauer carries out further specialist foundation engineering work for hydroelectric plant in Bhutan

Bauer works in an hydroelectric plant in Bhutan

The kingdom of Bhutan, located north of India is barely the size of Switzerland and dominated by the Himalayas, the highest mountains in the world.

Over 80% of Bhutan is 2,000 m above sea level. Mountains with a heigth of up to 7,500 m mark the highest points of the country. Many rivers span several thousand meters in altitude as they make their way from north to south, creating ideal conditions for hydroelectric power.

For this reason, Bhutan is pursuing an ambitious and above all sustainable energy policy: the kingdom already generates almost all of its electricity from hydropower, with the surplus being exported to neighboring India. Construction work has been underway on the large-scale Punatsangchhu-1 project since 2009 and Punatsangchhu-2 in 2013. Both hydroelectric plants are located on the Puna Tsang Chhu River, approximately 80 and 94

km from the capital Thimphu.

Bauer Spezialtiefbau GmbH had already been involved in the construction of the two hydropower plants in the past. In 2011, Bauer constructed diaphragm walls up to 80 m deep for the upstream cofferdam and executed injection work on Punatsangchhu-1.

Bauer returned to the site a few years later to carry out slope stabilization after a massive landslide on the right bank of the river. In 2014, Bauer was contracted to execute injection work to seal the Punatsangchhu-2 upstream cofferdam, a project that was successfully completed in 2015. "The Punatsangchhu-2 project involves the construction of a 90 m high dam, an 8.5 km long pressure tunnel and several caverns in the power plant complex," says Frank Berner, Operations Manager at Bauer Spezialtiefbau.

Bauer was again contracted to carry out specialist foundation engineering work for the project after an underground cavern collapsed at Punatsangchhu-2.

Bauer Spezialtiefbau GmbH was commissioned by main contractor Jaiprakash Associates Limited to carry out 18,000 m of soil injection for subsoil stabilization as well as to install 19,000 m of tie-back anchors. Along with various equipment for the injection work, up to five drilling rigs are being used at the same time, including KR 806 and KR 909 rigs from KLEMM Bohrtechnik GmbH. "The main challenge of this project is the cramped working environment. With a width of approx. 18 m and a height of 8 m, the work area is extremely small, creating an extremely challenging environment for equipment and personnel,” continues Frank Berner. "Also, we're in the Himalayas, which presents unique challenges for logistics." Bauer's work on Punatsangchhu-2 will take around 15 months.