多孔質材料の水理定数評価のための室内透水試験法の理論

Abstract

This paper reviews the development history of permeability tests for measuring the hydraulic constants (hydraulic conductivity and specific storage) of porous materials in a laboratory, and systematizes the theories of the methods. The permeability test originated from sand filtration experiments carried out by Darcy in the 19th century. Techniques for measuring hydraulic constants were then devised and, at the same time or successively, the theory was established. This paper presents the exact analytical solutions of six methods, including the constant head, falling head, flow pump, and transient pulse methods, with the same initial condition and different boundary conditions. Based on the analytical solutions, we demonstrated the variations in the hydraulic head distribution within a specimen and the variations in the sensitivity coefficients of the hydraulic head difference between both ends of a specimen in terms of the hydraulic constants and compressible storage at the upstream and downstream sides of the equipment during tests of the six methods. The results were used to characterize the test methods, in terms of the experiment time, experiment precision and error, and method selection.