Sainj Hydroelectric Power Plant
World record for long-distance concrete pumping to 2,432 km
Location: Himachal Pradesh, India
Market sector: Energy
Product used:MasterGlenium SKY 8787
Sainj Hydroelectric Project is a run of the river project on Sainj River in Kullu District of Himachal Pradesh, India. The project comprised of a diversion barrage, intake arrangement for drawing 35.88 cumecs of water, two underground de-silting chambers, a 6,300 m long, 3.85 m diameter modified horse-shoe shaped Head Race Tunnel (HRT), an underground restricted orifice-type 9 m diameter and 87 m high surge shaft, a 2.75 m diameter 550 m long steel-lined pressure shaft, two Pelton vertical axis turbines, each generating 50 MW power located in an underground power house.
Master Builders Solutions was commissioned by HCC to supply concrete admixtures for the construction of the HRT. The finished diameter of HRT is only 3.85m and in such a smaller diameter tunnel, vehicle movement and crossing are restricted, and carrying out multiple activities posed a severe challenge due to the congested working space. The movement of concrete conveying transit mixers is often restricted to one-way traffic only.
The temperature (ranging from 5°C to 35°C) and humidity inside the tunnel required an adequate ventilation system which created challenging working conditions as the tunnel length increased. To overcome these problems, long-distance concrete pumping is used for the concrete lining work of HRT.
While attempting long-distance concrete pumping, selection of concrete pump, the layout of the concrete conveying pipeline, selection and quality control of concrete materials, dealing with diverse climatic conditions, and the safe execution of all construction operations was crucial.
- Selection of concrete pump – Continuous inspections and maintenance to avoid breakdown and ensure the continuity of the long-distance pumping.
- Pipeline installation and maintenance – The right pipe diameter (150mm dia.) and thickness must be designed to withstand high pumping pressure.
- Concrete materials – The concrete mix must be able to meet the concreting requirements associated with pumping distance, temperatures, and relative humidity inside and outside the tunnel.
- Climatic conditions – The project is located in the Himalayan region where temperatures range from 5°C to 35°C.
- Safety – Pumping concrete over long distances involved working with high sustained pressure compared to conventional concreting. Safe working conditions like adequate ventilation and lighting are crucial.
With specially formulated concrete admixture MasterGlenium SKY 8787, the Smart Dynamic Concrete (SDC) technology improved the concrete mix characteristics by providing varying retention periods (4-12 hours) while maintaining workability. Most importantly, MasterGlenium SKY 8787 increased the flowability of the concrete mix, allowing concrete to be pumped up to 1,360 m upstream and 2,432 m downstream for the concrete lining works in the HRT.