Presented by Chris McGann
The presentation will be given by Chris McGann on his work undertaken with Brendon Bradley, Merrick Taylor, Liam Wotherspoon and Misko Cubrinovski, a summary of which follows.
Seismic piezocone data are used to investigate the applicability of several existing empirical correlations for predicting soil shear wave velocity (Vs) from cone penetration test (CPT) data, and ultimately to develop Christchurch-specific CPT-Vs correlations for estimating Vs in both the general alluvial and marine soils in the region and the loess deposits in the Port Hills. The correlations are validated through comparisons to Vs profiles obtained using surface wave analysis methods, and it is shown that the surface wave Vs and CPT-Vs values compare well in terms of their independently obtained Vs magnitudes.
The CPT-Vs correlations are applied to the large, high-spatial-density CPT dataset made available through the New Zealand Geotechnical Database to develop regional models of time-averaged shear wave velocity (e.g. Vs30) for the Christchurch region. These regional Vs models are then used to characterise the inherent depth variability of Vs in the region, to compare typical Vs values for the various geologic units encountered, and to investigate the effects of the observed depth variability on the expected seismic response for eight sub-regions of Christchurch. The regional models are also used to develop high-resolution site classification maps and to examine relationships between soil shear wave velocity, soil behaviour type index, and the severity of surficial evidence of liquefaction in a regional sense.
Kindly Sponsored by: Miyamoto International NZ