24-01-2020 - Appeal No. 245 of 2019 - Final Order of Judge Rackemann · 51987.2951.01

McInnes Wilson Lawyers

4.0       GEOTECHNICAL INVESTIGATION METHOD
The investigation fieldwork undertaken since the initial geotechnical report was produced (ref J000867-001-
R-Rev) has comprised seismic testing, borehole drilling and in-situ testing.
Test locations are shown on the attached Figure 1. The investigation was designed to accommodate the
significant access limitations associated with the site (e.g. overhead/underground services, limited space
between existing structures, sloping ground and retaining walls, and limited heavy vehicle access along
Seaview Terrace).
The fieldwork was undertaken under the direction of a geotechnical engineer from Core who logged
subsurface conditions encountered in accordance with AS1726-2017; directed the field testing; and made
groundwater observations during drilling. Test positions were recorded in the field using a handheld GPS
unit, and offsets from site features where possible.
The investigation fieldwork is discussed in more detail below.

    4.1       Seismic (MASW) Testing
Seismic testing in the form of multi-channel analysis of surface waves (MASW) was undertaken on 10 July
2019.
The seismic testing was undertaken along four alignments (designated Line 1 to Line 4, refer Figure 1), as
follows:

    ▪ Line 1: Along Seaview Terrace, west of No. 42 (about 60 m lineal length)
    ▪ Line 2: Along the southern boundary of No. 42 (about 60 m lineal length)
    ▪ Line 3: Along the toe of the dune, approximately a south-north alignment (about 60 m lineal length)
    ▪ Line 4: Across the lower portion/toe of the dune, approximately an east-west alignment (about 30 m
          lineal length).
The seismic testing investigation depth varied between about 25 and 35 m below ground level (BGL).
The seismic survey equipment and data acquisition parameters are summarised in Table 1.
The SurfSeis software by Kansas Geological Survey (MASW) was used to process the field data.
Experimental dispersion curves were obtained by selecting the peak amplitudes of the frequency-wavelength
spectrum of the fundamental mode. Inversion of the dispersion curves was then undertaken to estimate the
strata shear-wave velocities (vs) values.
Results of the seismic testing were correlated with the available geotechnical data, our previous experience,
and published information to provide an inferred subsurface profile along the test alignments.




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