REMEDEIAL MEASURES TO STOP SEEPAGE THROUGH TILLAR EARHTEN DAM BY TAM GROUTING DISTRICT SHAJAPUR (M.P.), INDIA
WATER RESOURCES DEPARTMENT, GOVERNMENT OF MADHYA PRADESH
16 KM FROM AGAR IN DISTRICT SHAJAPUR (M.P.), INDIA
PIONEER DESIGN CONCEPT, TAM GROUNTING THROUGH BODY OF DAM.
During the Fist impounding of water in Tillar dam in August 1987, area below toe of dam on downstream side had become marshy and water had started flowing in valley No. IV on d/s side. Immediately the reasons for seepage through body of earthen dam were analyzed. It was found out that water was seeping through the reverine deposit exiting between bottom of cut off trench and rock line of foundations. The permeability of this sensitive zone was in the range of 10-1 cm/ sec.
IT was decided to arrest seepage and reduce permeability from 10-1 cm/sec. to 10-4 cm/sec. by using cement-bentonite grout with TUBE-A-MANCHATTE grouting technique. This task was performed by providing three rows of grout curtain, 1.5 M c/c, and grout holes at 3 M c/c, staggered in each row. Four lines of piezometers 100 M c/c. have been installed. In one line, six piezometer, two numbers on u/s and four numbers on d/s of grout curtain were installed. A field laboratory was established to design cement-bentonite grout and to monitor grouting pattern properly. A test plot of 15 M length was initially taken to understand the acceptability of cement bentonite grout and to decide the parameter for further grouting pattern. Entire distress area of 340 M length was then taken up in hand and work was completed in one year time. The post grout permeability in entire reach has come down to 10-4 cm/sec. Four piezometer lines at 100 M c/c. were installed and by observing pre and post readings of piezometers, it was seen that differential head across the grout curtain has reduced by 88% measured at 90 M d/s from the grout curtain.