Information response - GEOTECH REPORT

Report: 15960, May 11 Page 3

2.6 To investigate subsoil details a single borehole was advanced by a small vehicle mounted
drilling tig and existing documents were reviewed. To augment the borehole, a dynamic cone
penetrometer test was advanced to assess soil strengths. Subsoil profiles are presented in APPENDIX A
‘with test locations shown on PLATE 1.

2.7 Boreholes revealed a residual clay profile. All clays were friable in structure, micaceous in
texture and ranged from low to medium/high plasticity values. Database tecords indicate these clays to
be moderately reactive and the Heltech Industries report concludes an Iss of 1.8. A weathered phyllite
rock within a clay matrix was noted below 1.2 metres. This soil structure continued to at least 3.0
metres. Similar soil profiles were recorded in the Heltech Industries report.
(8 Groundwater - No seepage or groundwater were noted with our fieldwork carried out
\cubSequent to a rainfall event.

2.9 Surface Movement - In accordance with AS2870 “Residential Footings and Slabs”, the Heltech
Industries report concludes an expected surface movement (Y,) ranging 45-50mm.,

2.10 General Definitions of Site Classes

 

Class Foundation Surface Movement

 

A Most sand and rock sites with little or no ground movement NIA
from moisture changes.

 

 

S Slightly reactive clay sites* with only slight ground movement.| 0mm <Ys £20 mm
from moisture changes.
M Moderately reactive clay or silt sites, which can experience | 20 mm < Ys £40 mm

moderate ground movement from moisture changes.

 

H Highly reactive clay sites, which can experience high ground | 40 mm < Ys 70mm
movement from moisture changes.

 

E Extremely reactive sites, which can experience extreme ground Ys >70 mm
movement from moisture changes.

 

P Sites which include soft soils, such as soft clay or silt or loose NIA
sands; landslip; mine subsidence; collapsing soils; soils subject
to erosion; reactive sites subject to abnormal moisture

 

 

conditions or sites which cannot be classified otherwise.

 

 

 

3. STABILITY RISK

 

3.1 In review of our detailed site walkover, document Teviewand 1 orehole investigation, we would
conclude the crown and near flank area of Lot 5 to be fa “low of brn impacting on person
or property.

 

 

Office at: 1/8 Denna St, Maroochydore, Q, 4558.
Phone: 5443 6622, Fax: 5479 1899, Email: [email protected]