Abstract:In order to complete the comprehensive investigation project of ecological restoration of Dongting Lake wetland, a standard sampling borehole was constructed that runs through the Quaternary loose mud and gravel layer in the Dongting Lake area, requiring accurate coring throughout the borehole. The construction task was successfully completed by adopting comprehensive measures such as increasing the core diameter, using small-diameter dry drilling for core extraction, and using large-diameter pipe wall protection. The core recovery rate reached over 95%, and the core was basically uncontaminated. A field application test was conducted on the aperture type special coring drilling tool, and the test results showed that the drilling tool can achieve better fidelity coring effect. However, there are still shortcomings such as insufficient length of the core tube of the drilling tool, which provides a basis for the improvement and promotion of the drilling tool. Through the construction of this borehole, a set of sampling techniques suitable for loose mud, sand and gravel layers in the Dongting Lake area has been explored, laying the foundation for the study of Quaternary ecological geology in the lake area.
