@article{oai:niigata-u.repo.nii.ac.jp:00028354,
 author = {森井, 俊廣 and 門口, 隆太 and 小松, 元太 and 松本, 智},
 issue = {2},
 journal = {新潟大学農学部研究報告, 新潟大学農学部研究報告},
 month = {Mar},
 note = {砂層とその下部に礫層を重ねた単純な構造の土層地盤では、互いの層の土粒子の大きさあるいは間隙サイズに伴う保水性の違いにより、砂層と礫層の境界面の上部で降下浸潤水が保水され、集積する。境界面に傾斜をつけると、集積水は傾斜方向に流下していくため、境界面はあたかも不透水性の障壁として機能し、それ以深の領域への水の浸入が抑制される。また、境界面に沿って流下した水は、末端で集水することにより、貴重な雨水資源として捕獲することも可能である。砂層と礫層を重ねた単純な土層地盤にみられる浸潤水の遮断・捕獲の機能を、土の毛管障壁あるいは土のキャピラリー・バリア（Capillary barrierof soil）と呼ぶ。傾斜したキャピラリー・バリアのもつ浸透抑制機能を利用すれば、地盤に浸透した降雨水を表層部で効果的に捕捉し、地盤深部への浸潤を低減できるため、地山斜面やため池堤防斜面などの斜面すべり防止技術への展開が可能となる。一方、キャピラリー・バリアを地表面の近傍で平面状に敷設すれば、土壌水を根群域に保水できるため、節水かんがいが可能となる。　このような土のキャピラリー・バリアがもつ応用展開の可能性に着目し、まず、土のキャピラリー･バリアの技術的特徴を紹介したのち、野外実験および圃場実験にもとづき、傾斜したキャピラリー・バリア地盤における雨水遮断機能ならびに水平状に敷設したキャピラリー・バリア地盤における節水かんがいの可能性を調べる。, Capillary barrier is the simple soil layer system which is composed of the fine soil (sand) layer underlain by the coarsesoil (gravel) layer. The capillary barrier soil was constructed in the natural sand slope, and the volumetric moisture contentsin the soil were successfully measured together with precipitations for about four months. Soil moisture changes in thegravel layer were well compared those in the sand layer to confirm a practically excellent divergence of infiltration wateralong the tilted interface between the sand and gravel layers. The percolation or breakthrough of the water flow along theinterface into the gravel layer was also observed. The divergence length of the capillary barrier where the percolation orbreakthrough into the gravel layer occurs was estimated using the soil properties determined by the laboratory tests andthe structural configuration of the capillary barrier soil. A fairly good correspondence of the divergence length between theobservation and the estimation demonstrated a practical effectiveness of the equation proposed by Steenhuis, Parlange andKung (1991). It may be concluded in the study that the capillary barrier soil system is possibly adaptable to the effectivemeasures for slope protection of natural soil or embankment. There is only a few studies related to this alternative measuresfor the slope protection. Rahardjo, Krisdani and Leong (2007) have proposed to use the capillary barrier as a soil cover forslope stabilization in tropical region, in which rather steep inclination of soil layers and high rainfall intensities are pointedout to be discussed. A multi-layered soil system of sand and gravel may be recommended to divert the infiltrated wateralong the interfaces completely and safely. A plant cover over the soil surface will decrease an amount of rain infiltration,and prevent soil surface deterioration of the capillary barrier soil due to raindrop erosion.A simple soil layer system which is composed of a fine soil layer underlain by a coarse soil layer has a characteristicproperty of capillary barrier. Water infiltrated into soil is stored just above an interface between the fine and coarse soillayers due to a physical difference in water retention characteristics of the fine and coarse soils. As their roots can easilyutilize the water stored in the upper soil layer, plants grow effectively even under water saving irrigation. In the study,an effect of water stored in the upper soil layer by the capillary barrier of the soil layer system on the plant growth wasinvestigated in the sand soil field. Six experiment plots, each 70 cm wide and 90 cm long, were excavated into the depth of40cm and veneer sheets were placed to retain soil wall, then the sand soil was filled back into the first two of six experimentplots along all the depth. A gravel layer 10 cm in thickness was placed at depth of 10 cm in other two experiment plotsand at depth of 20 cm in the remaining two experiment plots. Potherb Mustard was seeded and thinned after about threeweeks in all the experiment plots. Soil water changes in the experiment plot were measured after the plant seeding. Atabout 35days after the plant seeding, Potherb Mustard was harvested to measure plant height as well as dry mass of plant.It is found that the infiltration water was effectively stored in the upper soil layer by the capillary barrier of the soil layersystem, and the water stored in the upper soil layer affects significantly the plant growth. Further studies are required toexamine the effect of the capillary barrier of soil on the plant nutrition and to investigate the barrier property against saltconcentration caused by capillary rise of groundwater.},
 pages = {99--107},
 title = {土のキャピラリー・バリア機能を利用した雨水資源の保全・活用技術の開発},
 volume = {63},
 year = {2011}
}