【作者】 徐永年；

【导师】 匡尚富； 黄永健；

【作者基本信息】 中国水利水电科学研究院 ， 水力学及河流动力学， 2001， 博士

【摘要】 通过水槽实验，对崩塌土所能到达的最远距离进行了研究，成功地模拟了崩塌块体在饱和度较高的缓坡上快速滑行的现象。实验表明：松散崩塌土流动化机理为水流掺混，块状崩塌土流动化机理为压差减阻。给出了判别崩塌土相对运动距离，即流高比公式，并用现场实测资料进行了验证。提出了松散崩塌土和块状崩塌土流动化的判别条件。探讨了稠性泥石流在缓坡上加速运动的成因，并讨论了阵性泥石流平均流速公式。最后，分析了泥石流入汇对主河河型及河床演变的影响，讨论了泥石流入汇危险性评价的判别指标。主要内容如下： ·崩塌土运动距离的预测—崩塌土流高比与斜坡形状、崩塌源土质及沿程土质条件、坡前径流及土层含水状态等有关，并提出了崩塌土流高比公式。 ·崩塌土流动化机理探讨—松散崩塌土能否流动化取决于土体含水状态、纵坡，以及与水流掺混的程度，其流动化机理为水流掺混。块状崩塌土快速加载使其与下垫层之间出现超载孔隙水压力，且不能及时消散，减小了块体的有效重量，达到了减阻作用，其流动化机理为压差减阻。并提出了崩塌土流动化的判别条件。 ·泥石流的冲淤变化特性—泥石流多阵迭加过程中出现超载孔隙水压力使龙头阻力降低，在缓坡上能够加速运动，说明泥石流龙头迭加具有加速效应。对比了泥石流平均流速的各种公式，共同特点满足曼宁公式，修正后的公式精度较高。 ·泥石流入汇对主河影响—支沟泥石流入汇对主河的影响与交汇角、泥石流密度和规模的变化过程，以及主支沟水流的相互作用等有关，影响大小可用影响度、危险度和危害度等指标进行定量评估。更多还原

【Abstract】 The author successfully simulated the rapid sliding of avalanche soils on mild slope with saturated soils in flume experiments, and the longest distance that avalanche masses can move was studied. It shows that the collapsing of loose avalanche soil is due to mixing of avalanche soils and water flow, and the collapsing of block avalanche soils is caused by resistance decrease due to overload pore water pressure. And then the author established and verified an empirical equation for the ratio of the heights of collapsed part and running part for the avalanche soils,suggested the critical flow conditions of loose avalanche soils and block avalanche soils, discussed the causes of accelerated motion of consistent debris flows on mild slope, and studied the average velocity of intermittent debris flows. Finally, the author also analysed the effects of convergence of debris flows on main channel, discussed the discriminant index of hazard of debris flows rushing into the main channel.The forecast of moving distance of avalanche soils-The ratio of the heights of collapsed part and run-out of avalanche soils is related to slope shapes, avalanche sources, streamwise soil conditions, runoff on foreside, and soil moisture. An empirical equation for the ratio of heights for the collapsed part and running part of avalanche soils was established and verified.The flow mechanism of avalanche soils-Collapsing of loose avalanche soils depends on soils moisture, longitudinal gradient, and mixing flows of avalanche soils and water flow. In which, the formation of different debris flows was discussed. Flow of block avalanche soils is caused by the resistance reduction due to pore water pressure. The supernormal pore water pressure between the block avalanche soils and underlay reduces the weight of block avalanche soils as well as the resistance between the block avalanche soils and underlay. And then the author also suggested the critical flow conditions of avalanche soils.cour and silting characteristics of debris flows-Because of resistance decrease due to supernormal pore water pressure, intermittent debris flows can be accelerated on mild slope in the superimposable processes of several debris flows. It shows that the accelerated effects can be caused by the superimposition of head of debris flows. And then different average velocity formulas of debris flows were studied, they all accord with the Manning’s formula. These corrected formulas are very accurate.The effects of debris flows rushing into the main channel-The effects of debris flows rushing into the main channel are related to the angle between the gully and the main channel, the process of growth of debris flows, and the interaction of branch and main flow. The effectiveness can be expressed by the degrees of influence, danger and disaster of debris flows.更多还原