Design and development of a simple and easy-to-measure in-situ permeability test to determine hydraulic conductivity of soil.

土壤饱和和非饱和水分特性的原位测量对于准确预测农田、夯实土、天然边坡和垃圾填埋场等土壤中的污染物运移和水分运动至关重要。在研究项目中，实地和实验室调查进行了开发现场渗透性测试，其优点是测量数据的设备以及确定土壤渗透性的程序非常简单。现场渗透率测试由Guelph压力渗透仪（GPI）法和Guelph井渗仪（GWP）法组成，这两种方法都是由加拿大Guelph大学的研究人员提出的。GPI和GWP方法分别通过测量一个小深度的单环和一个更小深度的井对土壤的恒水头稳定渗透来确定土壤Kfs的现场饱和水力导电性。Kfs可以描述井水在土壤中的运动，因为许多自然和人为的渗透过程导致土壤中大量的空气夹持。在研究项目的第一年和第二年，通过实地调查、室内土仓试验和数值分析，验证了GPI和GWP方法的实际准确性和适用性。结果表明，GPI法和GWP法分别能准确有效地确定土体平面上和深度上的Kfs。还发现，土壤渗透性的统计特性可以确定，有效地通过GPI方法，因为它不需要一个繁琐的时间来确定一个地点的Kfs。对泥石流形成的砂土进行了原位渗透试验研究。根据试验结果和在实验室进行的砂土渗透性试验，有效地提出了确定砂土中包裹有大块砾石和鹅卵石的砂土水力渗透性的综合方法。在研究项目的最后一年，对原位渗透性测试进行了扩展，以便能够确定土壤的非饱和水分特性以及土壤的水导率。在恒水头入渗过程中，测量了GPI环或GWP井的入渗速率和土壤含水率随时间的变化，并通过数值反算估算了土壤参数，确定了土壤含水率、负压水头和非饱和导电性之间的最佳关系。少

It is well recognized that in-situ measurements of saturated and unsaturated moisture properties of soil are essential for accurate prediction of contaminant transport as well as water movement in soil such as agricultural field, compacted soil, natural slope and landfill. In the Research Project field and laboratory investigations are conducted to develop an in-situ permeability test that has a superior feature that an equipment to measure data as well as a procedure to determine the soil permeability is quite simple. The in-situ permeability test investigated consists of a Guelph pressure infiltrometer (GPI) method combined with a Guelph well permeameter (GWP) method, both of which have been proposed by the researchers of Guelph University, Canada. The GPI and GWP methods determine a field-saturated hydraulic conductivity of soil Kfs based on a measurement of constant-head steady infiltration into a soil from a single ring inserted a small depth into the soil and from a well bored a … More small depth into the soil, respectively. Kfs can describe well water movement in soil because many natural and man-made infiltration processes result in significant air entrapment within the soil.In the first and second years of the Research Project, a practical accuracy and an applicability of the GPI and the GWP methods were examined by a field investigation, a laboratory soil bin test and a numerical analysis. If is found out that the GPI and the GWP methods determine accurately and effectively Kfs in plane and along depth of soil, respectively. Also is found that a statistical property of the soil permeability can be determined,effectively by the GPI method because it does not require a tedious time to determine Kfs at a site. The in-situ permeability test investigated was applied to sand sediment soil formed by a debris flow of soil. From the test results and a permeability test of the sand sediment soil additionally conducted in the laboratory, an integrated procedure is effectively proposed to determine the hydraulic permeability of the sand sediment which is characterized by a inclusion of large gravel and cobbles into the sand soil. In the last year of the Research Project, the in-situ permeability test was extended so that it was able to determine unsat urated moisture properties of soil as well as the hydraulic conductivity of soil. Both an infiltration rate from the GPI ring or the GWP well and a moisture content of soil were measured during the constant-head infiltration with time, and were numerically back-calculated to estimate soil parameters which defined optimally unique relationships between moisture content, negative pressure head and unsaturated hydraulic conductivity of soil. Less