The River Godavari, revered for its life-giving waters, is also known for its fury during the monsoon season. Polavaram's Earth Cum Rock Filled (ECRF) dam will play a crucial role in taming this fury and providing water security to the people of Andhra Pradesh.
To support the ECRF dam, a 1.5-meter thick concrete wall called the D-Wall or Diaphragm wall is being built. It will be 1,400 metres long and extend 90 metres deep into the River's bed. This D-wall is the first of its kind in India and also the largest in terms of magnitude.
It is more than just a concrete structure - it's a safeguard against the immense water pressure exerted across the dam, which has a capacity of 190 TMC ft. and is designed to handle floods of up to 50 lakh cusecs.
This sub-surface wall will be anchored up to 2 metres deep beneath the river bed's rock strata, with depths ranging from 40 to 90 metres based on the geological composition. This ensures the dam remains stable and secure, even during extreme weather conditions.
Bauer is building this impermeable barrier under the supervision of the Central Water Commission (CWC) and an international Panel of Experts (POE), using specialised plastic concrete recommended by them.
The construction process is a marvel, with advanced equipment and specialised techniques employed to excavate and build the wall. It is constructed from plastic concrete and Bentonite slurry and carefully designed to prevent piping, foundation seepage, and erosion. With the construction of the D-wall, the quantity of concrete work is expected to increase to 63,656 square metres.
MEIL is supporting Bauer by handling key tasks such as producing plastic concrete and bentonite slurry, constructing guide walls, and managing logistics. Our expertise and resources are vital in ensuring the successful completion of the D-Wall.
The D-wall is being built between the Upper and Lower Coffer Dams to facilitate the construction of the ECRF dam in a dry environment, which is a herculean task.
As the D-Wall rises from the depths of the Godavari, it reminds us of the incredible feats of engineering that are possible when human skill and determination combine. These work quantities and metrics may vary according to the work situation and other factors.