Development Application Part 2 of 2 - Geotech Report and Plans - OPW13/0816

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                                                                                 Job No. 213-15522


     3.0     WALL CONSTRUCTION

     Provided site photographs and site inspections indicated that the revetment wall construction
     comprised a low height cast insitu concrete wall constructed on a short corrugated fibro
     sheet cut off wall. A three course blockwork retaining wall, with soil backfill, to have
                                                                                    appears
     been constructed on the revetment wall at a later date with a timber deck
                                                                                     supported on a
     high level footing system constructed behind the retaining wall.

     4.0     GEOTECHNICAL INVESTIGATION

     Subsurface conditions were assessed with four boreholes carried out from a work
                                                                                      boat,
     using hydraulically driven window sampling equipment and supplemented with Continuous
     Dynamic Cone Penetrometer tests (DCP’s)with three DCP’s carried immediately behind the
     temporary shotcreted revetment batter.

     Borehole depths ranged from 2.0m to 3.0m below existing creek bed levels. DCP tests were
     terminated at near penetration refusal at depths of 1.5m to 3.0m below
                                                                            existing creek bed
     levels and 4.5m to 4.8m below the existing ground levels behind the
                                                                                temporary
                                                                                     revetment
     batter.


    The field investigation, soil classification descriptions and field tests were carried out in
    general accordance with Australian Standards.

    AS 1726-1993             Geotechnical Site Investigation


    AS1289                   Method of Testing Soils for Engineering Purposes


    Notes relating to this report, Borehole Record Sheets, DCP test results and an Aerial
    Photograph/Site Plan detailing the location of boreholes are appended to this report.

    Field work was carried out on the 27th August and 24th September, 2013.


    Water levels were also recorded at varying offsets from the rear of the
                                                                       property to provide a
    general profile of the Weyba Creek bed immediately offset from the failed revetment wall
    location. The results are presented in brackets on the appended Aerial
                                                                             Photograph/Site
    Plan.


       4.1     Subsurface Profile

    The subsurface profile encountered in Boreholes 1, 3 and 4, comprised
                                                                                    very loose sand
    extending to depths of about 1.2 to 1.8m overlying medium dense to dense sand.

    At Borehole 2 location medium dense sands extended to about 1.2m and
                                                                         overlay dense
    conditions. The encountered very loose upper level subsurface profile is
                                                                             generally typical of
    active marine alluvial deposition process.


    DCP’s 5 to 7, located immediately behind the remaining revetment batter, encountered
                                                                                         very
    loose to loose and variable conditions to depths of 1.4m to 2.3m         medium dense to
                                                                        overlying
    dense conditions. The DCP’s were terminated at near penetration refusal in dense strata at
    depths of 4.5m to 4.8m below existing ground surface levels.




                                                    -;;: SOIL SURVEYS ENGINEERING PTY LIMITED
    1-15522,2013-09-20, LR VER 0