1-22276-01 site plan

Project No. 1-22276                                                                                                                  Page | 15
February, 2020
Ref: 1-22276, 2020-02-28, BR VER 2
Wessel Petroleum Pty Ltd – GEOTECHNICAL INVESTIGATION - Proposed Service Station Reconstruction, 52-54 Mary Street and Weyba Road,
Noosaville




Demolition and Clearing Activities

Extreme care should be exercised during the demolition/clearing phase to ensure that
excessive subgrade disturbance is not caused during removal of existing structures,
pavements, vegetation, services, etc.

Pre-Construction Meeting Service

Further, Soil Surveys Engineering offer a pre-construction meeting service. The primary
objective of this service is to allow the Contractor to demonstrate to the Principal and Project
Manager that they have a complete understanding of the earthwork challenges/risks associated
with this site (i.e. trafficability conditions, treatment of weak sandy soils, use of insitu soils as
structural fill, etc.) and that they have made appropriate cost and time allowances. Excavation
of trial pits by the preferred contractor (just prior to commission) should form part of this
exercise. Our standard rates will apply for this pre-construction meeting service. Please note
that this pre-construction meeting service is recommended for this project.

           6.2.3       Dewatering - Construction

The potential to encounter groundwater exists (refer Section 5.2).

For the deeper construction works e.g. tanks/pits/services/etc, a drainage system, comprising a
gravel blanket, side drains etc., grading to a sump pump, could be considered.

A groundwater study (consistent with Authority requirements) could be considered to assess
matters such as dewatering options (pre and post construction), the effect of groundwater on
foundation construction works, inflow/pumping rates, chemical composition of groundwater (to
allow assessment of groundwater disposal options), zone of influence of proposed dewatering
works (i.e. groundwater cone of depression), etc. Please note that it is important that
dewatering operations limit the extent of the groundwater cone of depression such that the
hydrological regimes that operate are not affected beyond the site.

           6.2.4       Excavation Characteristics

Excavations for the underground tanks and associated services, deeper footings, etc, will be
through the existing fill and natural sandy soils, including the indurated sand layer and possibly
into / through the natural clays.

Other excavations could be shallower, based in the existing fill and/or upper level sandy soils.

Should severe seepage be present in deep trench excavations, propping and shoring of the
trenches, particularly in the soils, may be required to prevent collapse, along with temporary
dewatering during excavation and laying of service lines.

The existing fill and natural soils have the potential to “collapse/fail” unexpectedly in a trenching
situation, particularly where seepage is encountered. Trenches excavated on this site should
be considered unstable; shoring of deep trench excavations are recommended. Suitable
precautions to satisfy Health & Safety requirements must be adopted. Construction procedures
(i.e. operation of plant, storage of materials, etc.) should also be considered in all safety aspects
of trenching works and other excavations.




                                                                                                            SOIL SURVEYS