22244-002-Rev1 Barina Ct

Mark Kussrow                                                                                   22244-002-Rev1
C/- CadCon Surveying & Town Planning                                                          26 February 2024

Clays if required for reinstatement are to be placed in layers not more than 200 mm (loose thickness) and
compacted by several passes of a pad foot roller to achieve a dry density ratio (DDR) of at least 95%
(standard) at a moisture content within +1% to +2% of the optimum moisture content.

Select rock fill shall be sound igneous or metamorphic material that will not disintegrate when exposed to
weather, or easily erode. Rocks should be fresh or slightly weathered, being of very high strength (or
stronger) as defined by AS1726. The least dimension of the rock should be not less than half its greatest
dimension.

Select rock fill could have the following grading:

          D50 (mm)      500-700
          D15 (mm)      250-350
          D85 (mm)      700-1000
          DMAX (mm)     1000

Rock fill shall be placed in such a manner that all relatively large stones shall be essentially in contact with
each other, and all voids filled with the finer rock to achieve a well graded, compact mass. Rock fill shall be
washed on adjacent areas, or prior to being transported to site, to remove fine material prior to handling and
placement. The rock fill must be ‘benched’ into the slope. Rock fill placement and compaction should be in
accordance with the mechanical interlock method as specified in Clause 15.4 of Main Road Technical
Standard MRTS04 General Earthworks.

5.2       Dam Monitoring and Maintenance
In general, make sure that the dam spillway is kept clear of debris and that the minimum freeboard of 1 m is
maintained at all times. The downstream face of the dam embankment should be planted out and kept free
from weeds. Trees, including small saplings, should not be allowed to develop on the embankment.

A maintenance inspection of the dam should be made following any rainfall exceeding 100 mm within 24
hours, during which the spillway, dam embankment and downstream toe area should be assessed, as
discussed below. It is recommended that the dam inspections should be undertaken by the property owner.

Should any signs of instability be observed, Tectonic and the design civil engineer should be advised
immediately to arrange a site inspection and determine an appropriate course of action.

The embankment should be examined for signs of cracks, piping, settlement, slides, and development of
seepage (on the downstream face). Any cracks should be filled immediately with well compacted clay.
There are three main kinds of cracks: transverse, longitudinal and shrinkage. Transverse cracks are those
that run straight through the dam from the upstream to the downstream side. Longitudinal cracks develop
parallel to the crest length. Shrinkage cracks develop in a random pattern of both transverse and
longitudinal defects. Cracks can also lead to another kind of failure known as piping, which is a term used
when seepage water creates a tunnel or pipe along a line of weakness through the dam.

Settlement in the crest should be rectified by building up the crest level to ensure that there is no overtopping
of the embankment, however such work should only be conducted under the direction of an experienced
geotechnical RPEQ.




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