Reference Document - MCU25 0101 (As Published)

 Project No. PG-13872                                                                                           Page | 10
 August 2025
 Ref: PG-13872, 2025-08-14, GR VER 1
 Stephen & Jane Struss – Geotechnical Investigation - Proposed Residence, 28 Kingfisher Drive, Peregian Beach




12.0 DEWATERING CONSIDERATIONS

Construction of the basement and foundation system will likely require dewatering.
The groundwater will need to be lowered to a minimum of 0.7m below the final
excavation depths, to allow the compaction of the founding soils to be achieved.
Groundwater was noted at approximately 2.5m below ground level and excavation
of up to 4m could be expected. Drawdown of approximately 2.5m is therefore
expected to be required.

Dewatering is typically achieved through the use of perimeter spears and internal
wells.

Settlements inducted by 2.5m of drawdown (i.e. 25kPa effective stress increase) are
estimated to result in settlements of less than 5mm. Therefore, it is considered that the
effects of dewatering on the adjoining structures will be minimal.

13.0 CONSTRUCTON MONITORING

Construction vibrations could potentially cause settlement in the loose upper level
sands, thereby damaging nearby structures founded in these strata. Prior to
commencement of construction on site, it is recommended that a detailed
dilapidation survey be undertaken to establish the condition of all existing adjacent
structures.

   13.1 Monitoring

It is recommended that monitoring points should be established on the retention
system to check for deflections during excavation. A suggested spacing of the
monitoring points would be 10m along the walls. A regular monitoring program of
these stations should be implemented.

Monitoring must commence before any excavation to establish baseline readings.

   13.2 Preconstruction Survey

Prior to commencement of construction on site, it is recommended that a dilapidation
survey be undertaken on the adjacent structures.

This survey should include the following:

          The extent of exiting damage (if any)
          The general condition of the property, ie. Condition of all exposed columns
           and beams, partition walls and cladding etc.
          Road, kerb and channel and footpath condition adjacent development site.