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INTRODUCTION

Narmada River is the 5th largest river in India and is known as the "Life Line" of Madhya Pradesh. Narmada Valley Development Authority (NVDA) proposed scheme the 12.6 cumecs of water from Hathani River (Tributary of Narmada) will be lifted to irrigate command area. The objective of the project is to increase the production of agriculture and improve the living standard of farmers in the designed command area of Alirajpur district (Madhya Pradesh).

PROBLEM

Scope of Irrigation project included the construction of four pump houses, an RCC distribution chamber, the main pipeline, a canal, and other related infrastructure facilities. Water will be lifted through suitable dia 25.14 km long M.S. Pipe rising main with a static head of 244 m in 3 stages (minimum lifting level of 110 m) and distributed to Command Area through RCC distribution chamber for catering water for irrigation up to 2.5 ha.

At the Pumping station (Ph1), there was a need to build Gabion Retaining wall. Our scope of work included Design, Supply & Installation of Gabion Wall 38.0meter High of “GTI” Make mechanically woven double twisted hexagonal shape steel wire mesh & Non-Woven Geotextile (300 GSM), Installation of Gabion Wall including Unboxing of Gabion Boxes at Sites, Placing of Boulder and Stones in gabion boxes, installation of Geotextiles behind the gabion wall & Dressing of Stones as required.

SOLUTION

GTI visited the site to provide site specific design solution.it was observed that terrain at site was a mixture of soil and rocks. In upper strata, rock was fragmented and highly weathered. With depth, weathering decreases and fractured to hard rock was encountered. The hill was partially cut and in the middle portion, Pumphouse was constructed by L& T and the cutting side slope was stabilized by constructing Gabion walls of height 38m by GTI.

Designers went through all geotechnical details. The main challenge was to design a 38m ht wall with a limited base area. Considering all site factors, we analyzed thoroughly then designed for submerged and dry condition and provided conservative design so that hill slope will remain stable under submerged condition. East and West Gabion wall design was carried out separately. GTI also provided extra reinforcement of GI wire mesh as additional measure.

The design of such High Gabion Wall requires a significant level of design experience and careful detailing to ensure ease of construction and satisfactory performance.

PROJECT CHALLENGES:

•  Designing and constructing of 38M High Gabion wall with limited base area.

•   Transportation of boulders 38m deep.

•  Side by side, construction of columns and tie-beam for pump house sump was going on so limited construction time as the rainy season was about to start.

For fast and efficient execution, it was recommended to use a Bucket/Basket attached to the cranes to reduce the time required for mobilization of boulders at 38m depth. Project work was huge and people were working day and night to complete the remarkable project.

In the rainy season Gabion wall, 38 m high Gabion wall was submerged under the backwater of the dam for a long time, Gabion wall was strong and cut slope was stable.

Execution of 38M High Gabion wall was Extreme Engineering as this is India's Highest Gabion Wall constructed till date. GTI has a team of experts who has been executing Gabion work more than a decade. Our execution team helped in the safe execution of this project.

CONCLUSION

L & T was very happy with the technical support provided by GTI ie Site Specific Design Solution, Timely and Good quality supply of material, and also provided fast and efficient execution of Highest Gabion Wall in India. This Remarkable project of 38 m High Gabion Wall was successfully constructed by Gabion Technology of India in June 2020.

Author :

Namrata Bichewar

Regional Manager - Maharashtra

Gabion Technologies India Pvt Ltd

Mobile: +91 93115 29115

Email : namrata@gabionindia.com