| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a water-collection/drainage control structure of a multilayered ground which prevents sand (fine-grain material) from penetrating between gravel (between coarse-grain material), and also reduces a layer thickness than water retentivity (a suction height) the sand layer (a fine-grain material layer) originally holds to also utilize water retentivity of the sand layer (the fine-grain material layer) positioned further above the sand layer (the fine-grain material layer) and improve CB effect by improving water retentivity as an entire group of the sand layers (the fine-grain material layer group) formed of multiple layers. <P>SOLUTION: The fine-grain material layer is formed on an upper part of the coarse-grain material layer. A first fine-grain material layer, which is formed of fine-grain material having a particle size smaller than that of the coarse-grain material, is formed on the upper part of the coarse-grain layer and has a particle size by which the grain is not mixed between the coarse-grain material. In addition, a second fine-grain material layer, which is formed of fine-grain material having a particle size smaller than that of the first fine-grain material, is formed on an upper part of the first fine-grain material layer and has a particle size by which the grain is not mixed between the fine-grain material of the first fine-grain material layer. <P>COPYRIGHT: (C)2012,JPO&INPIT |
