Evaluation of Cone Penetrometer Testing (CPT) for Use with Transportation Projects. Phase I: Feasibility Study

摘要

The ODOT Office of Geotechnical Engineering (OGE) currently uses conventional drilling methods (e.g., hollow stem auger, solid stem auger) to perform subsurface investigations in unconsolidated materials. These techniques have been used for decades and have the advantage of a long track record of experience and success within the state. These methods are, however, time-consuming and expensive to perform, do not provide continuous data, and are not well suited to some types of geologic and environmental conditions. Over the last 20 years, cone penetration testing (CPT) has been gaining acceptance in the U.S. and is now widely used as an alternative or complementary procedure to perform subsurface investigations. ODOT has funded this Phase I project to investigate how this new technology might be utilized to improve the quality and efficiency of ODOTs subsurface investigation program. This report presents the findings of this investigation and recommendations concerning Phase II implementation. The adoption of CPT for ODOTs subsurface investigation programs will save money through faster collection of data, collection of better and more consistent data, and collection of data that can be used directly in design work. An important upcoming need for ODOT is the mandate to move to LRFD design methods. CPT data can be used more directly with these methods, which will result in improve designs and savings on construction costs. The routine availability of a CPT rig will complement the existing conventional drilling equipment that ODOT now uses for subsurface investigation. For some projects, CPT will be used to replace conventional equipment. For others, CPT will be used in addition to conventional equipment to provide more accurate and different types of information and soil properties. For still others, the CPT may not be used at all. It is envisioned that the CPT rig will be used for major projects that require more detailed and extensive information about the subsurface. It will also be used to save money on a variety of projects.