Unified View of the Mechanics of Debris Flows and Sediment Laden Flows

泥石流和泥沙流力学的统一观点

• 批准号: 09450190
• 负责人: EGASHIRA Shinji
• 金额: $ 4.42万
• 依托单位: Ritsumeikan University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450190/
• 关键词: debris flow; sediment gravity flow; med flow; flow with bed-load; flow with suspended load; sediment transport rate formula; constitutive equations; 浮游砂流

This study has attempted a unified treatment of the following themes : the constitutive relationships of flowing water-sediment mixture, the profiles of sediment concentration and flow velocity from debris flows to flows with both bed-load, and "clear" water lagers to calculate the reference concentration of suspended flows. In this study, the constitutive relationships proposed by Egashira et al. include some physical parameters : the sediment size, the interparticle friction angle and specific weight of sediment etc.The effects of interparticle friction angle on debris flows have been investigated experimentally and theoretically for two years. The following results were obtained : in debris flows over rigid beds, an increase of interparticle friction angle causes flow resistance to increase. On the other hand, in debris flows over erodible beds, the inverse tendency appears.The influence of sediment size on flow of sediment-water mixture were investigated experimentally and theoretically. An experiment was employed with different sizes of sand, in the region from debris flows to the flows including a clear-water larger. The data obtained by flume tests were compared with the numerical simulated profiles of velocity, and sediment concentration. The calculated results agreed well with the flume data. The sediment transport rate became small when the sediment size was large, and became large when the sediment size was small for both large or small bed shear stress.Methods to predict the reference concentration and reference level of suspended flows were proposed using Egashira et al.'s constitutive relationships and taking the vertical distribution of the Reynolds' stress into account According to this method, the reference concentration was small when the sediment size was small. The calculated results were fitted with previous experimental data obtained by many researchers.

本研究试图统一处理以下主题：流动水沙混合物的本构关系，从泥石流到有床沙的水流的含沙量和流速剖面，以及用于计算悬浮流参考浓度的“清水”层。本研究采用Egashira等提出的包含泥沙粒径、泥沙颗粒间摩擦角和泥沙比重等物理参数的本构关系，对泥沙颗粒间摩擦角对泥石流的影响进行了为期两年的实验和理论研究。结果表明：在刚性床面泥石流中，颗粒间摩擦角的增大会引起流动阻力的增大。通过实验和理论分析，研究了泥沙粒径对泥沙-水混合物流动的影响。实验采用了不同尺寸的沙子，在该地区从泥石流的流动，包括清水较大。将水槽试验所得的流速、含沙量剖面与数值模拟结果进行了比较。计算结果与水槽试验数据吻合较好。对于较大的床面切应力和较小的床面切应力，输沙率随泥沙粒径的增大而减小，随泥沙粒径的减小而增大。的本构关系，并考虑雷诺应力的垂向分布。根据该方法，当泥沙粒径较小时，参考浓度较小。计算结果与前人的实验数据进行了拟合。

项目成果

江頭進治: "土石流の流動機構と氾濫・堆積域の解析-基礎理論からハザードマップまで-"1999年度(第35回)水工学に関する夏期研修会講義集. A-6-1-A-6-18 (1999)

Shinji Egashira：“泥石流机制和洪水/沉积区域的分析 - 从基础理论到灾害图”1999年（第35届）水利工程夏季研讨会讲座集A-6-1-A-6 -18（1999年）。 ）

Egashira, S.: "Mechanics of sediment transport and sediment laden flows (2.Sediment gravity flow)"Japanese Journal of Multiphase Flow. Vol.11 No.3. 258-262 (1997)

Egashira, S.：“沉积物输送和沉积物负载流的力学（2.沉积物重力流）”日本多相流杂志。

江頭進治: "流砂および流砂を伴う流れの力学(3.掃流砂の力学)" 混相流. 11・4. 388-393 (1997)

Shinji Egashira：“流沙动力学和涉及流沙的流动（3.底土力学）”多相流11・4（1997）。

江頭進治: "流砂および流砂を伴う流れの力学(3.掃流砂の力学)"混掃流. 11・4. 388-393 (1997)

Shinji Egashira：“流沙和流沙的动力学（3.床荷载力学）”11・4 388-393（1997）。

江頭進治 他: "土石流による河床侵食に関する実験的研究"水工学論文集. 43. 641-646 (1999)

S. Egashira 等：“泥石流引起的河床侵蚀的实验研究”水利工程学报 43. 641-646 (1999)。