閉塞浸透機構に関する研究 (3) -簡単なモデル実験による考察-

Abstract

In order to examine the mechanism of exchange of water penetrating to a ground andair in pore of a ground, the simplified experiments are carried out by using the U-shapedcapillary tube which is connected to the bottom of a cylindrical lucite bucket. The U-shapedtube has two straight glass tubes which are same or different size in inner diameter and theconfined infiltration is imitated by pouring the liquid of glycerin into the bucket quickly.Denoting the diameter of tube which air is discharged as d2 and the other as d1, it is foundout that in case of d2/d1≒1.0, the discharge process of air begins when the pressure of com-pressed air reaches nearly the value of the height of static capillary rise plus the depth ofponding liquid, and so on.Applying theses results obtained to the experiments of confined infiltration by the use ofsand column in a cylinder with bottom plate reported already, the followings are disclosed.(1) In infiltration into a homogeneous field of sand by ponding water on the sand surface, the quasi-saturated zone occures when the increasing pore-air pressure in the neighbourhoodof sand surface reaches nearly the value of height of capillary fringe and plus depth ofponding water.(2) The physical process of air discharge in confined infiltration can be understood, analogous to the discharging process of air in the U-shaped tube.