In-Situ in Christchurch provides direct measurement of soil and rock properties without disturbing the natural ground state, a critical requirement given the region’s complex fluvial and marine sediment deposits, liquefiable silts, and the stiff Port Hills loess. Our investigation programs integrate in-situ methods to address the seismic demands of NZS 1170.5 and the geotechnical investigation standards of NZGS Guideline Module 1, ensuring site characterisation aligns with the Canterbury Geotechnical Database and Environment Canterbury consent requirements. For sites with challenging access or where undisturbed sampling is impossible, In-Situ delivers continuous stratigraphic profiles and reliable engineering parameters that laboratory tests alone cannot provide.
Fieldwork adheres to New Zealand and international standards, including NZS 4402 for field density and ASTM D5778 for seismic piezocone. The cone penetration test (CPT) forms the backbone of our methodology, recording tip resistance, sleeve friction, and pore pressure to derive soil behaviour type, undrained shear strength, and equivalent SPT N-values. On granular materials, we perform the field density test (sand cone method) to verify compaction to NZS 4431 fill-control specifications. All data is captured with calibrated digital systems and referenced against the Canterbury earthquake sequence case histories to calibrate liquefaction triggering analyses using the Boulanger & Idriss or equivalent NZ-specific procedures.
Christchurch rebuild and land development projects routinely demand In-Situ for liquefaction assessment under the MBIE Module 4 guidance, foundation bearing capacity verification, and post-liquefaction settlement estimates. Residential subdivisions in Waimakariri, commercial structures in the Central City rebuild, and infrastructure corridors across the Selwyn-Halswell zone all rely on CPTu and shear-wave velocity profiling to satisfy the consenting requirements of Christchurch City Council. For fine-grained foundation soils, we combine in-situ vane shear testing with foundations design parameters to optimise shallow footing or pile configurations while managing the risk of cyclic softening.
A typical project begins with a desktop review of available Canterbury Geotechnical Database logs, followed by field deployment of tracked CPT rigs or nuclear-free density equipment with a chartered geotechnical engineer supervising all in-situ work. Deliverables include digital CPT data files (GEF or Excel), corrected geotechnical parameters, soil behaviour type charts, and a factual report cross-referenced to laboratory index tests such as grain size analysis (sieve + hydrometer) and Atterberg limits. The result is a defensible, council-ready dataset that reduces investigation uncertainty and accelerates foundation design on Christchurch’s variable ground.