Direct Validation of Design Parameters of Near-Surface Materials during Construction Phase

This overview paper discusses a number of innovative insitu test techniques that could potentially be incorporated into Quality Assurance / Quality Control (QA / QC) for the assessment of near-surface materials during the construction phase of earthworks projects. The limitations of traditional QA test regimes (density-based assessments) and other tests frequently adopted for field assessment during the construction phase of projects (CBR and DCP) are initially discussed, with a critique of the continued use of index tests for such material evaluations provided. A number of alternative test techniques that are capable of rapid, direct insitu measurement of stiffness and strength parameters is made, presenting the Light Falling Weight Deflectometer (LWD), Borehole Shear Test (BST) and Variable Energy Dynamic Cone Penetrometer (PANDA Probe) as viable alternative assessment methods. The insitu parameters provided by these alternative tests can be used to directly evaluate if design parameters are being met onsite and, based on the authors extensive experience using each tool within recent major Australian construction projects, the advantages of using such innovative tools and developing project-specific thresholds for adoption of these tools within a QA / QC test regime, are discussed. Current limitations preventing the widespread implementation of these alternative test techniques are also identified.