Study of a testing method for permeability of unsaturated soil with applied air pressure

结合三种饱和度测量方法，探讨了非饱和砂岩渗透率的测试方法。另一方面，利用FDM程序分析了土壤中孔隙空气/水的多相流行为。研究发现，承压条件下的饱和程度在砂柱内部有独特的分布趋势，实验结果也证实了这一点。考虑到混合流体的这一特性，并对应用气压式渗透试验装置进行改造，例如将两个滴管结合起来测量渗透量，我们在上一会计年度进行了非饱和砂和粉土的渗透试验，得到了一些具体的试验指导如下：(1)对于必要的与土壤相邻的过滤器，通过其材料的选择来评价其抗渗能力的修正对渗透性的影响。(2)试验发现土壤含水量分布独特，适宜采用1.0 ~ 3.0的水力梯度。(3)相对于以往非饱和土渗透性估算方法，高质量的双滴管渗流量测量系统实现了渗透性与饱和度关系的连续测量。

Testing method for permeability through unsaturated sands were examined in consideration of three measuring ways of saturation. On the other hand, behaviors of pore air/water in soil were analyzed by the use of FDM program for the multi-phase flow. It was found that the degree of saturation under confined air pressure was inclined to be uniquely distributed within sand column, which was also confirmed in experiment.Considering this properties of the mix fluids and reforming the permeability test apparatus in the applying air pressure type, for example,combining the two burette to measure seepage quantity, we performed permeability tests of unsaturated sand and silt in this last fiscal year, and obtained some concrete testing guides as follows.(1) As for the necessary filter abjacent to soils, the effect of correction of its resistance against seepage on permeability is evaluated with selection of its material.(2) Unique distribution of water content in soil and appropriate applied hydrauric gradient of 1.0-3.0 is recognized in the experiments.(3) High quality of measuring system of seepage quantity by two burette results in the continuous measuring way of the relation between permeabilty and degree of saturation, in comparison with the previously proposed methods for estimating permeability of unsaturated soils.