Keller has said that its work on jet grouting for cofferdams as part of the Polavaram dam project in India’s Andhra Predesh state has been completed on time in a first for the regional business.
The new dam on the Godavari River will provide irrigation, drinking water and hydrolectric power and work on the main dam started in 2015 but Keller’s work on the last year has focused on the upstream and downstream cofferdams.
Keller has drawn on its international expertise to deliver the work but has said that the experience has added to its jet grouting capabilities in India. The project is the largest jet grouting project delivered by Keller India.
The business unit was invited to bid for the project last year, which was originally to be delivered as a sheet-piling solution. However, this was deemed too inefficient due to practical limitations of depth and seepage cut-off and jet grouting was suggested as the best alternative option.
According to Keller India director Hari Krishna, the technology was only offered by a few Indian firms on a small scale so he brought in Keller’s jet grouting global product team for assistance.
“As a global company, Keller can handle the world’s largest jet grouting projects and has lots of ex-pertise in this area, so the team was able to help us bid for the job,” he said.
Expertise also came from all over the Keller world and included jet grouting expert John Willett and master driller Mark Fellows, both from Hayward Baker.
Over three months last year, the team meticulously planned every aspect of the job: the mix, equipment, safety, training and execution. After they successfully won the contract from client Transstroy, specialist jet grouting pumps were shipped from fellow Keller company Bencor, and Keller’s in-house equipment manufacturer KGS supplied the rigs, spares and mechanics. With the site in such a remote location, Keller had to ensure the team had everything it needed on site to keep the programme on schedule.
In total 110,000m3 of jet grouting has been completed over a 3km stretch, in columns of 2m diameter and up to 20m deep.
Work on the main dam is progressing with work scheduled to be completed next year. The dam is a 2.3km long rock and earth embankment dam with a 1.4km long diaphragm wall up to 95m deep to create a hydraulic cut off. The sale of the diaphragm wall, which is being constructed by L&T and Bauer, is reported to be record-breaking in India.