【第3回舗装工学講演会講演論文集 1998年12月】

舗装工学論文集 Vol. 3, 175-182, 1998.12

PERMEABILITY OF DRAINAGE BASE COURSE MATERIALS AT LABORATORY TESTS

Jianjun YIN¹ and Yoshitaka HACHIYA²

¹Dr. Eng., STA Fellow, Runways Laboratory, Port and Harbor Research Institute, Ministry of Transport (1-1, Nagase 3, Yokosuka 239-0826, Japan)
²Member of JSCE, Dr. Eng., Chief, Runways Laboratory, Port and Harbor Research Institute, Ministry of Transport (1-1, Nagase 3, Yokosuka 239-0826, Japan)

The permeability of five types of drainage base course materials (i.e. single-sized crushed stones that were either asphalt treated or untreated, sand, mechanical stabilized crushed stones, and drainage asphalt mixtures) were studied through constant-head permeability tests at laboratory. Three parameters (permeability coefficient k, turbulent flow parameters m and n) were introduced to describe the drainage behavior. Four aspects of the material properties, in terms of the average grain size dmean， void ratio, p2.36 and p0.075, were used to analyze the experimental results. The relevant findings were presented. It was indicated that errors might have been induced while using Darcy’s law to estimate the discharge velocity irrespective of the flow states.

Key Words: Permeability, drainage base course, laminar flow, turbulent flow, critical hydraulic gradient, Darcy's law

---

本論文では，単粒径砕石（アスファルト処理・無処理），排水性アスファルト 混合物，砂，粒度調整砕石という5種類の路盤材料に対して，室内定水位透水試験 を行い，それらの透水性能について研究している．材料の透水性能を表すパラメー ターとして3種類（k：層流，m，n：乱流）が導入され，物理特性を表すパラメー ターとして4種類（平均粒径dmean，空隙率，p2.36・p0.075 (2.36mm，0.075mm ふ るい通過分)）が導入された．一連の試験結果として，路盤材料の透水性能を表す 場合のDarcy則の適用性について明らかにしている．

---