RESTORATION AND REHABILITATION OF KRISHNARAJA SAGARA MASONRY DAM BY POINTING AND GROUTING

REHABILITATION AND IMPROVEMENTS TO KRISHNARAJA SAGARA DAM BY CONDUCTING DETAILED INVESTIGATIONS, ARREST THE SEEPAGE AND IMPROVING THE STRUCTURAL STRENGTH OF THE DAM

This restoration and rehabilitation work was executed under the DRIP program. The project was financed by the World Bank, and work was carried out under the technical supervision of the Central Water Commission. This dam, measuring 2.5 km, is a 100 years old dam with historic importance.

The rehabilitation of this dam involved the following activities:

• Upstream pointing with high strength, polymer-modified, UV resistant mortar
• Horizontal grouting of the upstream face
• Drilling and grouting from dam top for consolidation of the dam body.

The work started with cleaning the upstream face of the dam. After this, the old mortar was chipped off manually and the chipped surface was cleaned with a high-pressure water jet and air. The bond coat was then applied to a limited area and before it got dry, the fresh mortar was applied which arrested the seepage of water from the upstream face of the dam. The dam had a length of 2.5 km. and a height of around 20 m. To further stop the seepage of water, holes of 57 mm dia. were drilled up to a depth of 45-50 m in the dam body and the high-pressure grouting mixture of cement and special chemicals were pumped in.

The process of drilling into the dam body was a slow process involving manual effort & a hydraulic machine. In total, around 17 such machines are being deployed. Each machine was operated by a team of 5 members. Since the dam is very long, and no vehicles could move on the dam due to restricted width, herculean efforts was required to move the materials and machines from the end of the dam to the work location manually.