洞庭湖湿地生态修复松散泥沙砾石层取心技术

Coring technology in loose mud， sand and gravel layers for ecological restoration in Dongting Lake wetland

摘要:

为完成洞庭湖湿地生态修复综合调查项目，施工了一口贯穿洞庭湖区第四纪松散泥沙砾石层的标准取样钻孔，要求全孔保真取心。采用了增大取心口径，小口径干钻取心，大口径跟管护壁等综合手段，顺利完成施工任务，岩心采取率超过95%，岩心基本未受污染。进行了光圈式特种取心钻具现场应用试验，试验结果表明，该钻具可以取得更好的保真取心效果，但还存在钻具岩心管长度不足等缺点，为该钻具改进与推广提供了依据。通过本钻孔的施工，摸索出了一套适合洞庭湖区松散泥沙砾石层的采样技术方法，为湖区第四纪生态地质研究奠定了基础。

Abstract:

In order to complete the comprehensive investigation project of ecological restoration of Dongting Lake wetland， a standard sampling borehole was constructed， which runs through the Quaternary loose mud， sand and gravel layers 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 coring diameter， using small-diameter dry drilling for core extraction， and large-diameter casing wall protection. The core recovery rate reached over 95%， and the core was basically uncontaminated. A field application test was conducted about the aperture type special coring 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， which provides a basis for the improvement and promotion. 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.