IMHE OpenIR  > 山地灾害与地表过程重点实验室
降雨滑坡形成机理及预测方法研究
Alternative TitleStudy on the mechanics of rainfall-induced landslide and its prediction method
Language中文
罗渝
Thesis Advisor何思明
2013
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Name博士
Degree Discipline岩土工程
Keyword降雨滑坡 临界降雨值 滑坡危险性 饱和-非饱和渗流 稳定性 滑坡运动 危害范围
Abstract我国是世界上滑坡灾害最严重的国家之一。在滑坡的诱发因素中,降雨是诱发滑坡的主要因素。一直以来对降雨滑坡的研究都是学者们热衷的研究课题之一。然而目前对于降雨滑坡的研究,在其形成机理及预测方法的研究方面存在某些不足之处,主要表现在:(1) 现有的降雨临界值计算模型大多建立在统计学基础上,缺乏明确的物理力学基础,不能考虑边坡地形地貌、地质环境条件、局地降雨特性对滑坡稳定性的影响;(2)研究中没有考虑降雨滑坡灾害链的特性,将降雨滑坡从降雨入渗-滑坡启动-运动-运动停止的各个过程分开对待,不能够真实的反应降雨滑坡的实际过程特性。因此,本文以降雨滑坡形成的物理力学机理研究为基础,建立物理力学基础明确,综合考虑地层下垫面特性和降雨特性的滑坡降雨临界值计算模型;从降雨滑坡灾害链的特性出发,考虑降雨入渗-滑坡启动-运动-运动停止各个过程的联系性,研究降雨滑坡灾害链的形成机理,揭示降雨作用下边坡土体含水量变化、孔隙水压力分布规律,分析孔隙水压力变化对边坡稳定性的影响,确定边坡最危险滑移面分布,构建降雨滑坡运动物理模型,进行降雨滑坡运动速度与危害范围预测。研究分别以“区域降雨滑坡”和“典型降雨滑坡”为研究对象,展开降雨滑坡形成机理及预测方法研究,具体研究内容和研究成果如下: (1)对于区域降雨滑坡,根据坡地降雨入渗的物理过程,建立坡地水文模型,研究降雨入渗过程中边坡地下水响应规律。论文从降雨入渗致使边坡坡面有、无坡面流产生两种情况出发,分别建立其坡地水文模型,揭示了土体结构特性以及不同降雨强度、降雨类型、时间和前期降雨对地下水的影响,同时对于有坡面流产生的情况,揭示了不同降雨强度、时间对坡面流流深的影响。 (2)基于坡地水文模型,研究降雨入渗对边坡稳定性的影响,建立降雨临界值计算模型。论文基于无限边坡理论及摩尔-库伦破坏准则结合坡地水文模型,建立边坡稳定性计算模型,揭示了地下水位、坡面流深度变化对边坡稳定性的影响。综合坡地水文模型和边坡稳定性模型,分别针对边坡坡面有、无坡面流产生两种情况,建立降雨诱发滑坡的降雨临界值计算模型,该模型物理力学基础明确,同时能够将降雨强度、降雨类型、降雨历时以及前期降雨的影响考虑在内,将该模型应用于都江堰降雨滑坡危险性分区中,其研究结果证明了模型的合理性和可靠性。 (3)对于典型降雨滑坡,基于饱和-非饱和土渗流理论,利用有限元方法,研究降雨入渗对土体含水量、孔隙水压力的影响。研究结果表明:降雨条件一定时,土体的饱和渗透系数是影响坡体孔隙水压力、入渗深度以及体积含水量的关键;当降雨强度大于土体的饱和渗透系数时,在相同的降雨持时下,降雨强度的增大,对边坡孔隙水压力、体积含水量的影响不大;降雨强度小于土体的饱和渗透系数时,在相同的降雨持时下,随降雨强度增大,边坡内的孔隙水压力、体积含水量也逐渐增大;当降雨量相同,降雨持时越长,降雨的入渗深度越大,孔隙水压力、体积含水量越小;在降雨量和降雨历时相同时,不同降雨类型下的土体含水量和孔隙水压力分布是不同,降雨类型对边坡的瞬态渗流场影响不容忽视。 (4)基于饱和-非饱和土抗剪强度理论,考虑负孔隙水压力作用对边坡稳定性的影响,将降雨作用下的瞬态渗流场与极限平衡法相结合,研究不同饱和渗透系数、降雨强度、降雨历时以及降雨类型对边坡稳定性的影响。研究结果表明:在降雨条件一定时,土体饱和渗透系数不同,边坡的安全系数是不同的;当降雨强度大于土体饱和渗透系数时,增加降雨强度对边坡安全系数的影响较小,而当降雨强度小于土体饱和渗透系数时,增加降雨强度对边坡安全系数的影响大;当降雨历时相同时,降雨强度越大,边坡安全系数下降的越快,同时降雨结束时边坡的安全系数越小;当降雨总量一定时,边坡的安全系数随着降雨历时的增加而减小;当降雨总量和降雨时间相同时,降雨类型不同边坡的安全系数是不同的。 (5)考虑降雨滑坡的运动特性,建立降雨诱发滑坡的运动物理模型,进行降雨诱发滑坡滑动的运动速度、滑动距离以及危害范围的预测研究。论文将整个滑坡的运动看作是一个质点组的运动,针对滑动面为圆弧面的滑坡,进行滑坡运动的相关研究,建立其运动物理模型,进行降雨滑坡的运动速度和危害范围的预测,实现了完整的降雨滑坡灾害链过程的研究,为滑坡灾害的危害评估和预测提供理论和技术支持。
Other AbstractChina is one of countries with seriously landslide disaster. Among the landslide trigger factors, rainfall is the main factor. Research on rainfall-induce landslide is traditionally one of the most favorite topic for researchers. Nevertheless, in present research there has some insufficiency. Its basically behave in: (1) rainfall thresholds is major defined by statistic-based method. The statistic-based method may ignore the physical processes of rainfall-induce landslide and the effect of slope topography, geological conditions and rainfall characteristics on slope stability haven’t been considered; (2) rainfall-induce landslide chain has been ignored, separated the rainfall-induce landslide chain processes of rainfall infiltration, slope failure, movement and stop. So, this paper based on the physical mechanics of rainfall-induce landslide to construction the rainfall thresholds compute model. Therefore the model has the physical mechanics foundation and the effect of underlying surfaces and rainfall characteristic on slope stability can be take into account togerther; then consider the connection of each rainfall-induce landslide chain processes, as rainfall infiltration, slope failure, movement and stop to study on the mechanics of rainfall-induce landslide. The researches are revealing about the pore water pressure and water content varies with the rainfall infiltration. The effect on the slope stability of pore water pressure changes and the distribution of the critical sliding surface are analyzed. At last, the physical movement model has been established, which is use to predicting the velocity and the damage range of rainfall-induced landslide. The paper has chosen “regional rainfall-induce landslide” and “local rainfall-induce landslide” as the objects of study, and the research contents and results as follow:
(1) For regional rainfall-induce landslide, based on the process of rainfall-infiltration to construction the hillslope hydrology model, and then study on the changes of  groundwater by the rainfall infiltration. Rainfall infiltration result in these two conditions: the overland flow occurring and not occurring on the hillslope. So the paper take the above two conditions into consider to establish the hillslope  hydrology model respectively, and apply the model to research the effect of soil haracteristics, rainfall intensity, rainfall type, time and antecedent rainfall on the roundwater. Meanwhile, the effect of rainfall intensity and time on the overland low also been studied.
(2) Based on the hillslope hydrology model to study the effect of ainfall-infiltration on the slope stability and then construction the rainfall thresholds ompute model. The paper used the infinite slope theory, M-C fracturing criterion and combine with the hillslope hydrology model to establish the model for slope stability analysis. And then research on the effect of groundwater and overland flow on the slope stability. Finally, the author use the hillslope hydrology model combined with the slope stability model to construction the rainfall thresholds compute model for the overland flow occurring or not occurring on the hillslope respectively. The rainfall thresholds compute model has physical-mechanical foundation and can take rainfall intensity, rainfall type, time and antecedent rainfall into account together. At last, this model was used to make Dujiangyan province landslide susceptibility zonation, and the results show the model is rational and reliable.
(3) For local rainfall-induce landslide, based on the saturated-unsaturated seepage theory and using the FEM method to research the effect of rainfall infiltration on water content and pore water pressure. The result shows: the saturated hydraulic conductivity is the key factor of water content and pore water pressure at constant rainfall. When the rainfall intensity is larger than the saturated hydraulic conductivity, water content and pore water pressure has little change by increase the rainfall intensity under the same time. Otherwise, water content and pore water pressure increase by increase the rainfall intensity. At the same rainfall, the longer rainfall time the deeper rainfall infiltration, and the smaller water content and pore water pressure. When the rainfall and the rain time is the same, different rainfall types result in different water content and pore water pressure. The effect of rainfall type on the transient infiltration field can’t be ignored.
(4) Based on the saturated-unsaturated shear strength theory, take the effect of negative pore water pressure on slope stability into account, apply the transient infiltration field combine with the rigid equilibrium limit method to research the effect of the saturated hydraulic conductivity, rainfall intensity, time and rainfall type on slope stability. The result shows: different saturated hydraulic conductivity result in different safety factor of slope at constant rainfall. When the rainfall intensity is larger than the saturated hydraulic conductivity, the safety factor of slope has little change by increase the rainfall intensity under the same time. Otherwise, the safety factor of slope has more obvious change by increase the rainfall intensity under the same time. The larger rainfall intensity the more dropping fast of safety factor of slope and the smaller value of safety factor of slope. The longer rainfall time the smaller safety factor of slope under the same rainfall. When the rainfall and the time are constant, different rainfall types result in different value of safety factor of slope.
(5) Moving character of rainfall-induce landslide has take into account to establish the moving physical model for landslide. In this paper, landslide moving have been seems to be a group of particle moving, for the circle landslide surface, the moving physical model has been constructed. And then, predicted the moving velocity and displacement for landslide. The research for an integrated rainfall-induce landslide process come true. The results may provide theoretical basis and technical support for landslide hazard assessment and prediction.
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/7047
Collection山地灾害与地表过程重点实验室
Recommended Citation
GB/T 7714
罗渝. 降雨滑坡形成机理及预测方法研究[D]. 北京. 中国科学院研究生院,2013.
Files in This Item:
File Name/Size DocType Version Access License
罗渝:降雨滑坡形成机理及预测方法研究.p(3030KB) 开放获取CC BY-NC-SAView Application Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[罗渝]'s Articles
Baidu academic
Similar articles in Baidu academic
[罗渝]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[罗渝]'s Articles
Terms of Use
No data!
Social Bookmark/Share
File name: 罗渝:降雨滑坡形成机理及预测方法研究.pdf
Format: Adobe PDF
This file does not support browsing at this time
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.