IMHE OpenIR  > 山地灾害与地表过程重点实验室
降雨型堆积层滑坡起动的物理力学机制
Alternative TitleMovement Mechanism of Accumulation Landslides Triggered by Rain
Language中文
刘超
Thesis Advisor苏立君
2016
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Name博士
Degree Discipline岩土工程
Keyword优先流 降雨入渗 分形理论 多尺度 堆积层滑坡 降雨阈值
Other Abstract

堆积层滑坡在我国分布广泛,危害严重,其稳定性问题已经引起了各国学者的高度重视。降雨型堆积层滑坡的起动是一个复杂问题,涉及了大气圈、水圈、岩石圈等众多圈层内的多个过程,其问题的研究尺度跨度非常大,小到孔隙尺度,大到流域尺度。堆积层滑坡的坡体物质是由土与石混合体组成的,其成因以坡积、冲洪积为主,极其复杂,通常也被叫做宽级配砾石土。在降雨条件下,非饱和区内通常以优先流的形式入渗,这也是研究降雨型堆积层滑坡起动的关键。传统的均质入渗模型基于有压入渗的条件,通常表现为湿润锋面的前进,它没有考虑优先流的作用,仅适用于浅层滑坡。为了研究降雨入渗的机制,本文中展现了一种优先流形式的入渗模型,该模型从孔隙的分形结构出发,根据入渗特点,对孔隙进行分区(初始含水量区、基质区、优先流区),体现降雨入渗的不平衡分布。在这种优先流的入渗形式下,研究堆积层滑坡内水土相互作用,进一步研究坡体稳定状态与降雨入渗之间的定量关系。主要成果如下:(1)建立了一种能够体现优先流特征的降雨入渗模型。该模型具有以下特征:第一,在非饱和土中入渗;第二,入渗量和入渗率在空间上不平衡分布,体现了土体孔隙的多尺度结构性;第三,在宏观上,入渗深度随着雨强的变化表现出了多尺度的特性,是解释降雨阈值机制的关键;第四,由于入渗的水量的不平衡分布,供给饱和带的水量随时间呈现非线性变化的特征;第五,坡体的材料因素以及降雨条件等均会影响入渗的特性。 (2)在优先流入渗模型的基础上,建立了降雨型堆积层滑坡起动的尖点突变模型。模型中体现了包气带内优先流的入渗形式与坡体内土体之间的相互作用,以及这些作用对坡体起动的贡献机制,解释了降雨阈值的产生机理,研究了降雨强度、累计降雨量对坡体起动的影响。通过起动模型归纳了导致堆积层滑坡起动的因素,包括坡体内部的材料因素(如孔隙率、饱和渗透系数),外界的环境因素(如降雨强度、累计雨量),以及体现前期气候条件的坡体初始含水量,并且定量的研究了这些因素对坡体起动的作用。

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Accumulation landslides have aroused researchers’ great attention with their wide distribution and serious risk at home and abroad. The movement of accumulation landslides caused by rainfall is composed of many physical and mechanical processes in the atmosphere, the hydrosphere, the geosphere and so on, which is a complex problem. This problem has a great scale from soil pore to river basin.The material in this type of landslides,mainly slope sediments, fluvial and alluvial materials, is a kind of soil and rock mixture with complicated causes, which is usually called as wide grading soil.This soil has the multi-scale characteristic to gestate the preferential flow in unsaturated zone of landslides during rainfall, which is a key point to the study on their slide mechanism.Traditional homogeneous infiltration model with surface water pressure for depicting the steady motion of the wetting front was only adaptable to the shallow landslides without considering the phenomenon of the preferential flow in wide grading soil. For investigating the rainfall infiltration mechanism, a preferential flow model was proposed by introducing the fractal theory to depict the fractal structure of soil pores in considering infiltration-dependent division regions: the initial water content region, the matrix region and the preferential flow region. The infiltration characteristics of each region (the initial water content region, the matrix region and the preferential flow region) was investigated under rainfall intensity and the initial water content in interpreting the formation mechanism of the preferential flow. Based on this infiltration model, water-soil interaction and the influence of infiltration on landslide stability are studied quantitatively. Following is the main achievements:(1) A preferential flow model was proposed to interpret the mechanism of rainfall infiltration. This model applicable to unsaturated zone reflects the multi-scale soil pores structure and unbalanced distribution of rainfall infiltration, which provides saturated zone with the nonlinear water flow. In this model, varying tendency of infiltration depth with rainfall intensity reflects a multi scale characteristics, which is a main point for threshold values of rainfall precipitation. Soil material and rainfall factor can both affect the infiltration characteristic. (2) A landslide movement model based on cusp catastrophic theory and the preferential flow infiltration characteristic has been set up. This model reflects the mechanism of threshold values of rainfall precipitation and the influence of water-soil interaction on the landslide stability. This model is used to study the quantitative influence factors of landslide movement. These factors include soil material (porosity and saturated infiltration coefficient), rainfall characteristic (rainfall intensity and accumulation precipitation) and local climate characteristic (initial water content of soil). 

Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/18917
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
刘超. 降雨型堆积层滑坡起动的物理力学机制[D]. 北京. 中国科学院大学,2016.
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