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Use of Drilling Parameters for Enhancing Geotechnical Site Investigations

项目名称：	Use of Drilling Parameters for Enhancing Geotechnical Site Investigations
摘要：	The standard penetration test (SPT) is a proven tool widely used in providing disturbed soil samples to aid in geotechnical site characterization along with estimating soil properties for the design of New Hampshire Department of Transportation (NHDOT) projects. Testing and sampling is typically done at 5 to 10 foot intervals and thus between these samples, use of engineering judgement identifies changes in stratigraphy and the soils respective properties. These tests are used to develop recommendations and aid in the design of NHDOT projects. Performing the SPT in a continuous fashion can be time consuming and labor intensive. The test is also not well-suited for soils containing large particles such as gravel. A technique known as Monitoring-While-Drilling (MWD) makes use of the mechanical response of the drill rig and cutting tools while advancing a borehole. When combined with SPT testing, a continuous quantitative drilling record is produced and the correlated parameters applied into the analysis. This will result in a thorough and accurate representation of subsurface conditions leading to safer and more economical designs. MWD is recognized as an underutilized site characterization tool by the Federal Highway Administration EDC-5: Advanced Geotechnical Methods in Exploration (A-GaME) initiative. The proposed research will assess the use of MWD on roadway and bridge foundation projects for NHDOT. The drilling parameters recorded will be compared to measurements traditionally collected by SPT and the associated soil samples, along with rock cores for deep foundations. Drilling machine parameters controlled by the operator will be collected such as: thrust on drilling tool, rotation rate, and drilling fluid rate. Parameters that directly correspond to the ground response will be collected such as: advance rate, torque, fluid injection pressure and drilling fluid return rate. Other non-controlled parameters will be evaluated to include tool wear and changes in drilling fluid composition. This effort will support more efficient use of design and construction resources and reduces the chance of delays due to unexpected subsurface conditions. Additionally, the information will make an important contribution to the NHDOT Geotechnical Manual and can support mapping efforts and water quality studies performed by other agencies.
状态：	Active
资金：	$159,757
资助组织：	New Hampshire Department of Transportation
项目负责人：	Nash, Deirdre
执行机构：	University of New Hampshire, Durham
开始时间：	20210505
预计完成日期：	20230831
主题领域：	Bridges and other structures；Geotechnology