Environmental Engineering Reference
In-Depth Information
2A and 2B filters where invariably one might seek materials satisfying carefully specified
particle size grading limits and dense hard durable materials.
8.3.2
Examples of embankment designs
8.3.2.1
Zoned earthfill dams
Figures 8.3 and 8.4 show examples of zoned earthfill design. Both were designed for low
or very low consequence of failure classification sites. The Tahmoor damsite was under-
lain by sandstone and there were limited sources of non-dispersive earthfill. The sand-
stone rock breaks down to a silty sand when compacted in thin layers, yielding an
acceptable transition filter material. The design (which was done by the first author)
would be improved if Zone 2 was taken to the top of Zone 1 to provide filter protection
under flood conditions.
The Blair Athol Dam was built over alluvium, and over an existing dam, which had
been built without conventional design or construction control. A cutoff trench was exca-
vated to the weathered sandstone and siltstone foundation. Zoned earthfill construction
Figure 8.3.
Mine water supply Tahmoor Dam (courtesy of Coffey Geosciences).
Figure 8.4.
Water storage dam, Blair Athol Mine (courtesy of Coffey Geosciences).
