Polavaram D-Wall works to begin after Sankranti

The delay is due to pending clearance from the Central Water Commission (CWC), which is reviewing recommendations from an international experts’ panel on the plastic concrete composition for the wall.
Polavaram Diaphragm Wall
Polavaram Diaphragm WallPhoto | Express
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VIJAYAWADA: The construction of a new Diaphragm Wall (D-Wall) at the Polavaram project, costing an estimated Rs 990 crore, is expected to commence after Sankranti.

The delay is due to pending clearance from the Central Water Commission (CWC), which is reviewing recommendations from an international experts’ panel on the plastic concrete composition for the wall.

According to sources, the project contractors and officials submitted three different compositions of plastic concrete for evaluation. The panel, after an in-depth review, forwarded its recommendations to the CWC, which is likely to decide within three to four days.

Initially, Chief Minister Nara Chandrababu Naidu had announced that construction would commence on January 2, but technical requirements, including the final approval of the concrete composition, caused a postponement. Preparatory and investigative works for the project began in November. Project officials stated that the plastic concrete would be prepared onsite under the supervision of experts from Bauer, a German company. This self-hardening, waterproof material prevents water seepage in underground spaces. Unlike rigid concrete, plastic concrete’s ductile properties make it resistant to cracking under pressure, ensuring its effectiveness in preventing seepage. A senior engineer explained that cracks in rigid structures allow water leakage, whereas ductile materials withstand pressure and maintain integrity.

Polavaram Diaphragm Wall
Andhra Cabinet approves construction of new diaphragm wall for Polavaram project

The proposed 1,400-metre-long D-Wall addresses seepage issues, with bentonite being a critical component to enhance the concrete’s plasticity and workability. The new wall will incorporate expert recommendations and be constructed six metres upstream of the existing structure, which was damaged by floods in 2019 and 2020. Project authorities revealed that the sub-surface wall will extend up to two metres into the rock strata beneath the riverbed, with depths ranging from 40 to 90 metres depending on the riverbed’s geological composition. The CWC approved the wall’s new design in late November, and construction will proceed in phases based on expert committee guidelines.

This single-structure D-Wall will run parallel to the damaged wall, ensuring robust flood resilience and enhanced water retention capacity for the Polavaram project. The introduction of plastic concrete in its construction underscores a focus on durability and long-term effectiveness, critical to the project’s success.

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