大口径蒸渗仪原状土柱取样实用技术

Technique of Sampling Natural Soil Column for Large-diameter Lysimeters

原状土蒸渗仪由于土体结构没有被扰动,可以保持其自然属性,是开展田间水文模拟的理想设施,但土体取样精度不易控制。结合五道沟水文实验站大口径蒸渗仪原状土柱取样实践,针对蒸渗仪原状土柱取样如何快速精确修整、罐体内壁和柱体间的空隙尺寸如何把控、土柱切割如何控制尽可能不被扰动等,系统提出其取样工艺流程和关键技术,发明了铣刀精修土柱法和切土刀板快速切土法,避免了人工修土带来的柱体表面不均匀不光滑、土柱切割不整齐等问题,尽可能减少原状土体结构的扰动和罐体内壁与土柱之间的边界效应。实验表明,罐体内壁与土柱间的空隙2mm可以保持蒸渗仪运行后原状土体的自然属性,从而提高蒸渗仪实验模拟的真实性。

This paper aims at studying a key technique for how to fix the inner wall that can rapidly and accurately control inter-eolunm void size and avoid being disturbed by cutting the soil eolunm during the process of sampling natural soil eolunm using large-diameter lysimeters.And it systematically proposed the sampling process combined with the practice of sampling natural soil at the Wudaogou hydrological experimental station.Besides, it invented the method of the refined soil column of milling cutter and the method of rapid soil cutting of soil cutting knife,which avoid the problems of rough surface and irregular incision of the soil column brought by using traditional long knife to repair soil manually. Moreover, the methods can reduce the disturbance of the natural soil structure and the boundary effects as much as possible.The experiment has shown that when the gap between the inner wall of tank and the soil column is 2mm, the natural properties of natural soil can be maintained after the operation of lysimeter.Thus,the reality of the lysimeter simulation experiment has been improved.