海岸樹林によるエネルギー損失を高精度に評価する津波解析モデルの構築と適用

准确评估沿海森林能量损失的海啸分析模型的构建和应用

• 批准号: 10J07964
• 负责人: 飯村 耕介
• 金额: $ 0.9万
• 依托单位: Saitama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for JSPS Fellows
• 财政年份: 2010
• 资助国家: 日本
• 起止时间: 2010 至 2011
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10J07964/
• 关键词: 津波; 海岸樹林; 二層林; 樹林密度; マングローブ

近年,海岸樹林の津波減災効果が注目されており,本研究では樹林モデルの高精度化のためにマングローブ林などの気根を有し,鉛直方向に大きく構造が変化する樹木を対象に,気根層を再現した植生模型を配置して水理模型実験を行い,上下層の密度比がもたらす流速や抵抗力への影響を明らかにした.植生模型は気根層を再現した植生模型(二層林モデル)とそれを鉛直方向に平均した植生模型(一層林モデル)の2ケースで検討した.二層林モデルでは樹高8mのマングローブ林の100分の1縮尺程度を参考に,高さの異なる直径2mmの木製円柱を組み合わせて配置した.下層部分の高さは20mmで円柱の中心間距離は8mm,上層の円柱の中心間距離は24mmとなる.一方,一層林モデルは直径5mmの木製円柱を24mm間隔で配置した.多くの研究,特に樹木抵抗を考慮した解析では,樹木の抵抗は水深積分化されて導入していることが多く,本研究の一層林モデルも二層林を水深積分化して与えている.二層林の下層部分は正三角形配置なので,その投影幅は円柱直径の6倍となり,投影幅を水深方向に平均すると4.5mmとなる.一層林ではこれとほぼ等価の幅を持つように5mm円柱を使用した.植生模型が無い条件に比べて,二層・一層林ともに植生帯前面で反射や堰上げにより最大水位が大きくなり,植生帯の背後で水位が低減した.二層林では下層部分に植生が偏って存在するため,一一層林に比べて植生帯前面での反射・堰上げの効果が小さくなった.二層林の場合は下層部の植生帯の密度が上層部に対して大きく,上層部で流れが加速し,下層部で流速が低下する.上層の流速は下層に比べて最大2.6倍となったが,植生帯全体における平均的な抵抗力は一層林のほうがわずかに大きい.そのため,植生帯前面での反射が大きく,抵抗もわずかに大きい一層林のほうが二層林に比べて背後における低減効果が大きくなることが分かった.

In recent years, coastal forest Tsuha has attracted much attention. In this study, the plant model is configured, the hydraulic model is configured, and the roots are located in the straight direction. The density ratio, the flow rate, the resistance, the density, the flow rate, the resistance, the resistance, the density, the flow rate, the resistance, the resistance, the density, the density, the flow rate, the resistance, the resistance, the density, the density, the flow rate, the resistance, the resistance, the density, the density, the flow rate, the resistance, the resistance, the density, the flow rate, the resistance, the resistance, the density, the density, the flow rate, the resistance, the resistance, the density, the density, the flow rate, the resistance, the resistance, the density, the flow rate, the resistance, the resistance, the density, the density, the flow rate, the resistance, the resistance, the density, the density, the flow rate, the resistance, the resistance, the density, the flow rate, the resistance, Plant model (2) average plant model (1) plant model (1) plant model (1 The height of the forest is 8m high, the height of the forest is 8m, the height is 8m, and the height is 1m. Lower section height 20mm column center distance 8mm, upper column center distance 24mm column distance. On one side, the diameter of the forest, the diameter of the 5mm, the diameter of the wood, the column, the 24mm, the configuration. Multi-tree research, special wood resistance research, analysis, wood resistance, water depth differentiation, wood resistance, water depth differentiation, wood resistance, wood resistance, differentiation, differentiation and differentiation. In the lower part of the forest, there is a regular triangle configuration, the projection frame is 6 times the diameter of the column, and the average projection amplitude is 4.5mm depth. In the first place, you can hold the 5mm column and use the column. The plant model has no condition to compare, the maximum water level on the reflection Weir in front of the plant plant is very high, and the water level in the back is low. In the lower part of the forest, there is a slight deviation of the plant, and the fruit is smaller on the reflection Weir than in the front of the plant. The lower part of the forest plant density, the upper part, the lower part, the lower part. The upper and lower flow rates are 2.6 times higher than the maximum, and the average resistance of all plants is higher than that of the whole population. In front of the plant, the reflection is large, and the resistance to the first forest is lower than that in the back.

项目成果

Experimental Investigation for the Effects of Tree Arrangement in a Forest on Mitigating Tsunami

森林树木布置对减缓海啸影响的实验研究

• 发表时间: 2011
• 作者: Kashida;H.; Sekiguchi;K.; Higashiyama;N.; Kato;T.; Asanuma;H.;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・浅沼浩之;加藤智博・樫田啓・浅沼浩之;加藤智博;加藤智博;Kosuke Iimura;飯村耕介;Kosuke Iimura
• 通讯作者: Kosuke Iimura

Dangerous Zone Formation Behind Finite-length Coastal Forest for Tsunami Mitigation

用于减缓海啸的有限长度沿海森林后面危险区域的形成

• 发表时间: 2012
• 期刊: Journal of Earthquake and Tsunami
• 影响因子: 1.5
• 作者: Kashida;H.; Sekiguchi;K.; Higashiyama;N.; Kato;T.; Asanuma;H.;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・浅沼浩之;加藤智博・樫田啓・浅沼浩之;加藤智博;加藤智博;Kosuke Iimura
• 通讯作者: Kosuke Iimura

樹林密度の異なる植生帯を組み合わせたときの津波軽減効果に関する研究

不同树木密度植被带组合的海啸减灾效果研究

• 发表时间: 2010
• 期刊: 土木学会論文集B2(海岸工学)
• 作者: Kashida;H.; Sekiguchi;K.; Higashiyama;N.; Kato;T.; Asanuma;H.;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・岸田英夫・矢田祐之・岡本博・浅沼浩之;加藤智博・樫田啓・浅沼浩之;加藤智博・樫田啓・浅沼浩之;加藤智博;加藤智博;Kosuke Iimura;飯村耕介
• 通讯作者: 飯村耕介