用于砂土层连续采样的柔性软袋式钻取采样技术研究

Technology of Coring Drill with Flexible Tube for Sand Layers Continuous Sampling

摘要:

砂土是地球表面常见的一种覆盖物，由于风力和水力的搬运作用导致传统浅层采样器所采集的样芯信息量不足，并且由于砂土颗粒之间的内聚力小流动性大，传统环刀压入方法无法采集到长度大于20cm并且具备连续层序信息的样品。为此提出一种柔性软袋式取芯技术，采用内置柔性袋取芯机构的外螺旋钻具对砂土进行钻取采样，以提高采样的样芯长度并保持层序信息。分析了取芯钻具与砂土相互接触的机理以及对采样样芯的扰动情况，通过仿真模拟的比对揭示了传统环刀压入法对样芯扰动的原因。搭建了试验台并针对传统环刀压入法与柔性软袋式取芯方法的采样率进行了对比试验，结果显示后者取芯率随转速增加下降10.4%，前者随压力增加提高16.4%，使用柔性软袋方法取芯率均值从13.08%提高到84.08%，并能保持连续的样芯层序信息。

Abstract:

Sand layer is a common covering material on the surface of earth. The sample can provide more information for geological analysis in the area. Sand particles were carried by water and wind easily. Therefore, the shallow sample obtained by traditional cutting ring method would lose some important characters. For the high fluidity and low cohesive of sand, the traditional cutting ring sample method cannot collect the samples from the length greater than 20cm with continuous layers information. A new sample drilling technology with flexible tube mechanism was proposed to resolve this problem. It was composed by flexible tube which was fixed in the auger. The sample drilling technology had ability to increase coring length and protect layers. The contact principle and disturbance between the coring drill and sand were analyzed. Based on the simulation results analysis, the reasons for the failure of continuous sampling were revealed. An experimental bench was built to test the difference between the traditional cutting ring and flexible tube drilling method on sampling rate. The results showed that the coring rate was decreased by 10.4% and increased by 16.4% to the flexible tube and traditional cutting ring, respectively. The sampling rate and efficiency of flexible tube were much higher and less adverse the sequence of sand layers. The coring rate of flexible tube was increased from 13.08% to 84.08%.