卡口地形段泥石流的堵溃效应研究

The block-breach phenomena tend to occurrence when debris flows run throng bayonet section, accompanying with instant scale-amplified effect; Block-breach effects of bayonet section in the debris flow gully have been apt to more significant in the earthquake suffered region since Wenchuan earthquake. At present, researches towards debris flow rarely referred to the Erosion-deposition and block-breach effects in bayonet section of debris flow gully, with lacking of specific determinative method for block-breach effects, and the block coefficients can but evaluate experientially, thus the accuracy of the debris flow motional parameters design are questionable. Therefore, we are absorbed in the study on Erosion-deposition processes and block-breach effects in bayonet sections of debris flow gully. By the way of field investigation as well as indoor experiment, this research plans to study the regularity of erosion-deposition in bayonet section of debris flow gully, analyze the influence factors and formation mechanisms, By means of quantitative expression for topographic feature of the so-called bayonet, the research will explore the critical condition and determinative method for block-breach effects when debris flows occur, reveal the amplification effect for motional parameters of debris flow through bayonet section, and finally put forward computing method for block coefficient. The proposed project will provide knowledge for motional and deposited regularities of debris flow where microrelief abruptly changed, and complement for debris flow mitigation and control technology. The project has important theoretical significance and application prospects.

泥石流在流经卡口段沟道时常出现暂时堵溃现象，泥石流规模产生瞬间放大效应；汶川地震以后，震区泥石流在卡口段的堵溃效应更加显著。目前，有关卡口段沟道泥石流的冲淤与堵塞效应的研究较少，缺少具体的堵溃发生的判定方法，堵塞系数只能定性率定，泥石流运动参数设计存在很大的不确定性。因此，本项目以卡口段泥石流的冲淤与堵溃效应为研究对象，通过典型卡口段泥石流野外调查和室内水槽实验的方法，研究卡口段泥石流的冲淤规律，分析堵溃效应的影响因素与成因机制；以定量参数表征卡口地形特征，探索泥石流发生堵溃的临界条件和判定方法，揭示卡口段泥石流流量的放大效应，进而提出卡口段泥石流堵塞系数的计算方法。本研究对认识泥石流在微地貌突变条件下的运动、堆积规律，完善泥石流防治技术规程方面都具有重要的理论意义和应用前景。

泥石流在流经卡口段沟道时常出现暂时堵溃现象，本研究以岷江流域映秀~汶川段为研究区域，采用野外调查、测绘结合室内模型试验的方法，开展卡口段泥石流堵溃过程与冲刷堆积过程的研究，并通过野外资料进行验证，项目研究成果对认识泥石流在微地貌突变条件下的运动、堆积规律，完善泥石流防治技术规程方面都具有重要的理论意义和应用前景。.1、项目首次对卡口段泥石流的运动参数、冲淤特征进行了详细的调查与勘测，分析了卡口的成因，并根据不同的分类指标对卡口进行了分类研究，探讨了卡口段泥石流堵溃过程的影响因素，分析了卡口段泥石流的冲淤特征。.2、通过室内泥石流模型试验，定量分析了各影响因素对泥石流堵溃、泥石流冲淤特征的影响，建立了卡口段泥石流流量比及一次泥石流总量过程衰减的计算公式。.3、提出建立泥石流三维地质模型的方法，进行了卡口段泥石流的流固耦合分析，探讨卡口对泥石流运动与堆积过程的影响。.4、通过野外调查资料与研究成果进行了验证，并结合泥石流防治工程实例进行了应用研究。