REHABILITATION OF OLD DAMS, STRENGTHENING BY DRILLING, GROUTING AND POINTING OF TIGHRA DAM, GWALIOR (M.P.) INDIA.
Client : Water Resources Department, Government of Madhya Pradesh.
Location: 16 Km From Gwalior City (M.P.) India
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This dam on river Sank was constructed in the year 1917, with lime mortar stone masonry. The foundations rest on massive sandstone. It had breached in the very first filling and was reconstructed by 1929.
In the last years, due to ageing, the dam had been leaking at a number of points downstream. Water was gushing out heavily at a few places and most of the lime mortar had flushed out of the masonry joints at the others. Before grouting operations, pointing in rich cement mortar was done on u/s and d/s face of the dam.
To arrest the seepage and consolidate the body of the 915-metre long dam, we drilled and grouted the entire length of the dam and provided a 2 m wide grout curtain on the u/s face of the masonry dam. The holes were drilled 6 m apart, and staggered in two rows 2 m apart. Wherever the seepage was heavy, secondary holes were drilled and grouted. The average depth of the grout curtain was 24 metres. This treatment reduced the seepage within permissible limits. After the grouting was completed, inclined release holes were made in the body of the masonry dam to release the poor pressure, along a line about 15 ft d/s from the heel of the dam, and 50 feet centre to centre.