間隙水圧形の測定から得られる粘性底層厚さを用いた土石流の相似則の検討

利用孔隙水压力形状测量得到的粘性底层厚度检验泥石流相似律

• 批准号: 13760112
• 负责人: 堀田 紀文
• 金额: $ 1.28万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Young Scientists (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13760112/
• 关键词: 土石流; 間隙水圧; 粘性底層; 粗度; 相似則

本研究は,土石流における粘性底層厚さと流れの状態(層流・乱流)の関係を相似則として検討することを目的としている.具体的には,レイノルズ数の代表長さの項に粘性底層厚さを用い,限界レイノルズ数における粘性底層厚さと水深の比から,流れの状態を判断する.前年度の研究結果である,・相対水深(水深/粗度)が10程度以下の土石流で粗度面での粒子衝突の影響が顕著で,流れの摩擦抵抗が増大する・濃度が高い(0.35〜)流れにおいて上記の粗度の影響が大きいに加えて,本年度は以下のような結果が得られている.・粗度による影響の生じている流れでは土石流の流速分布は,3/2乗則から外れて直線分布に近い・低濃度の土石流において,間隙水圧が従来の構成則から導かれる間隙水圧の値に比べて大幅に小さいものとなる以上の結果を総合すると,固定床上の土石流に対する相似則の適用に際して,粘性底層厚さを導出するために,現在の構成則の内,間隙水圧によって生じる応力成分について修正を加えなければいけない事が理解される.また,土石流において,層流〜乱流への遷移領域に属する流れは,底面粗度の影響を受けている可能性が高いため,粘性底層を含んだ流れの構造を議論するためには,底面粗度の影響を底面境界条件などの形で従来の構成則に含む必要があることが示された.摩擦抵抗係数と,上述のレイノルズ数から求まる粘性底層厚さの比較より,比較的濃度が高く,相対水深が大きく粗度の影響を受けにくい土石流においては,粘性底層厚さが水深と同程度で,流れが層流とみなせる事を確認した.

This paper discusses the relationship between the viscous layer thickness and the flow state (laminar flow and turbulent flow) of debris flow. Specific, the number of representative length, the thickness of viscous layer, the ratio of viscous layer thickness to water depth, and the state of flow are determined. The results of previous year's study showed that: ·The effect of particle collision on debris flow with depth (depth/thickness) less than 10 degrees was significant, and the friction resistance of flow increased.·The concentration was high (0.35 ~), and the effect of thickness on flow was significant.·The results of this year's study showed that: ·The velocity distribution of debris flow due to the influence of thickness is different from that due to the linear distribution due to the influence of thickness. The velocity distribution of debris flow due to the influence of thickness is different from that due to the linear distribution due to the influence of thickness. The velocity distribution of debris flow due to the influence of thickness is different from that due to the linear distribution due to the influence of thickness. The velocity distribution of debris flow due to the influence of thickness is different from that due to the linear distribution due to the influence of thickness. The velocity distribution of debris flow due to the influence of thickness is different from that due to the influence of thickness. The velocity distribution of debris flow due to the influence of thickness is different from that due to the influence of thickness. The velocity distribution of debris flow due to the influence of thickness is different from that due to the influence of thickness. The velocity distribution of debris flow due to the influence of thickness is different from that due to the influence of thickness. Now the composition of the internal, gap water pressure is generated by the force component of the correction is added to the understanding. Debris flow, laminar flow, turbulent flow, migration domain, flow, thickness of bottom, influence of structure, viscous bottom, thickness of bottom, boundary condition, shape and composition of bottom, influence of flow, thickness of bottom, influence of structure, thickness of bottom, influence of structure, influence of bottom, influence of structure, influence of structure The friction resistance coefficient is determined by comparing the thickness of the viscous layer with the thickness of the viscous layer. The thickness of the viscous layer is determined by comparing the thickness of the viscous layer with the thickness of the viscous layer.