Geotechnical Report

    J000206-001-R-Rev0                                                                                     April 2016


5.0      GROUND CONDITIONS
           Published Geology
The 1:100,000 series Gympie Special geological map (Sheet9445 and Part 9545, DME, 1999) indicates that
the site is underlain by Late Triassic – Jurassic, Duckinwilla Group – Tiaro Coal Measures ‘Lithofeldspathic
siltstone’ close to the boundary with Quaternary age estuarine channels and banks comprising ‘sandy mud,
muddy sand, minor gravel’.




                                                                                           Indicative site location




Plate 1 – Geological Map
           Subsurface Conditions
The general subsurface profile encountered in the test pits comprised:
      TOPSOIL: comprising silty clay with traces of rootlets and organics to depths of between 0.1 m and 0.3
       m below ground level (BGL); overlying

      NATURAL SOILS: comprising stiff to hard silty clay to the depth of investigation of 3.5 m BGL; except in
       test pits TP1, TP3 and TP6 which encountered

      SILTSTONE: Extremely low strength, extremely weathered from depths ranging from 2.5 m to 2.8 m
       BGL to the depth of investigation (i.e. 3.5 m BGL).

Groundwater was not encountered in any of the test pits. It is noted that groundwater seepage may occur in
permeable horizons within the soil and rock, particularly following periods of heavy or prolonged
rainfall.Laboratory classification test confirms field classification and indicates that the clay materials are high
plasticity and highly reactive to moisture content variation.




                                                         4