Study on application status of direct push drilling technology in contaminated site investigation

Abstract:

Drilling technology is the only scientific method that can directly obtain formation samples in the investigation of contaminated sites. Direct push drilling technology has the advantages of no drilling fluid， flexible maneuverability， fast drilling speed， and small sample interference. Based on the existing domestic and foreign study， this paper compares and analyzes the structure and propulsion process characteristics of the Spanish TEC15 and the United States 7822DT rigs. The latter has higher static propulsion and pull-out force. Single pipe and double pipe are studied， and the structural composition and sampling process of the two direct push drilling tools. The results indicate that because the PVC sampling sleeve is set in the single pipe， the integrity of the soil sample can be effectively maintained and the efficiency is high. Nuclear magnetic resonance （NMR）， soil hydraulic testing （HPT）， membrane interface detection （MIP） technical principles and equipment composition are introduced， and MIP has greater technical advantages for the three-dimensional concentration detection of pollutants. The development status of domestic direct push drilling technology and equipment is also analyzed， combined with the geological conditions of contaminated sites in China and research status， pointed out that the portable integrated equipment and technical verification of advanced drilling and in-situ detection that can achieve precise control is the main development trend.