1 - GEOTECHNICAL INVESTIGATION REPORT - 150320 LAR Road Investigation Ridgewood Geotech 23042015_Rev1-Combined

Design should incorporate positive drainage to reduce the potential for water ponding on or
adjacent to the roadway. Ponding of water could potentially give rise to saturation of fill
materials and increase the risk of slope instability.

7. 2 Recommendations for Batter Re-Profiling
It is understood that the proposed re-profiling of batters and reinstatement of the table drain
will entail excavation and trimming of some of the existing cut faces along the length of the
road upgrade. Based on observations made during the site walkover and summarised
above, slope angles of 45 to 55 degrees as detailed on the L&R design drawings are
considered appropriate and achievable provided that provision is made for a flatter batter
(maximum 1 Vertical to 2 Horizontal) within the top layer of residual soil which is typically in
the upper 1 m of the cut profile where slumping of these soils was evidenced on site.
Alternatively, a bench could be formed at the interface between residual soil and weathered
rock. Benching or battering in these upper soils will minimise maintenance issues and the
likelihood of slumping material entering table drains.

It should be recognised that the dense vegetation at the crest of existing batters is assisting
stability, and that re-profiling will remove trees and shrubs, including some significant trees
along the section shown on Drawing REE-TFR-004.

Excavation and trimming of the rock batters may be undertaken using a medium excavator.
An irregular finished profile could result where there is bedded material with medium
strength rock and if encountered these areas may require some additional treatment to aid
long term stability. The use of rock breakers may be beneficial in producing a more regular
profile in these areas. The resulting re-profiled batters should be inspected by a geotechnical
engineer, to advise on any remedial works (if required) to maintain stability.

8.0 Limitations
The data and advice provided in this report relate only to this project and must be reviewed
by a competent geotechnical engineer before using for any other purpose. Red Earth
Engineering Pty Ltd (REE) accepts no responsibility for other use of the data.

The advice provided in this report is based on information provided by Lambert & Rehbein
Pty Ltd (L&R) and is not warranted in respect to the conditions that may be encountered
across the site at other than the locations investigated. It is noted that ground conditions can
vary between locations other than where observation, explorations and investigations have
been made.

REE accepts no responsibility for the accuracy of data (soil properties etc.) provided by
others. REE also accepts no responsibility or liability for assessments made to provide
indicative/preliminary results where site specific investigations have not been carried out.
The assumptions used for such assessments have been clearly outlined and results are
presented as a guide for L&R.

Due to the inherent uncertainties in subsurface conditions (associated with natural and
unnatural processes), changed or unanticipated subsurface conditions may occur that could
affect the project cost/time and execution. REE does not accept responsibility for the
consequences of unforeseen variances in the conditions and the requirements for the
execution of the work.

The subsurface and surface earthworks and excavations should be examined by a suitably
qualified and experienced geotechnical engineer who shall confirm that the revealed ground



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