Environmental Engineering Reference
In-Depth Information
Changes to the dam design were made during construction, to allow for the potential
for water to penetrate along open joints under the upstream part of the earth core, to min-
imise the possibility of adverse deformation of the core, and to allow the unstable slope to
be quickly restrained. The adopted measures included:
-
Steepening of the upstream face of the earth core from 1:1 to 0.25 H:1 V (Figure 2.33);
-
addition of a secondary downstream grout curtain, and blanket grouting between the
two curtains (Figure 2.33);
-
extending the lower half of the cutoff trench about 25 m downstream, and immediate com-
mencement of placing the upstream rockfill, in advance of the earth core zone placement.
In addition to the above, extensive dental treatment of open joints (with mortar) was
carried out in the cutoff trench, and backfill concrete was placed over the badly disturbed
and weathered rock at the upstream edge of the cutoff trench on the right bank, shown on
Figures 2.31
and 2.33.
Figure 2.33.
Tooma Dam, cross sections of original and rezoned embankment (Hunter, 1982).
