【作者】 杨文东；

【导师】 李新平；

【作者基本信息】 武汉理工大学 ， 结构工程， 2006， 博士

【摘要】 滑坡是一种严重的岩土体失稳现象，降雨原因引起的滑坡称为降雨型滑坡。滑坡的发生固然离不开不良的地质条件和岩土体结构条件等内因，但另一方面离不开各种外部营力的作用，引起滑坡的外部营力有很多种，在诸多外部营力中，降雨尤其是大量的降雨或暴雨无疑是触发滑坡的最主要的因素之一。降雨对滑坡的触发作用主要体现在：在降雨过程中，地表水进入岩土体增加了坡体的自重，增大了孔隙水压力，使处于极限平衡状态的坡体产生滑动；降雨由地表进入地下，转变成为地下水，浸泡软化滑动面，降低了坡体的抗剪强度；坡体多次的干湿交替变化导致岩土体开裂，产生大量的节理裂隙。研究表明，在具备了滑坡的地势和地质条件时，降雨在很大程度上是滑坡发生的最主要激发因素。国内外许多学者对降雨与滑坡的关系进行了很多有效的探索，他们采用不同的方法或模型来研究某个区域滑坡产生时雨强或降雨持续时间的临界值，在一定程度上说明了降雨与滑坡之间的关系，从不同的角度探讨了降雨对滑坡的作用，为深入开展降雨型滑坡的研究奠定了良好的基础。本论文在综合前人研究成果的基础上，搜集了部分区域多年的滑坡和降雨历史资料，应用系统分析法、数量化理论、渗流理论和数值分析法等理论方法，对降雨型滑坡特征、降雨型滑坡过程与过程控制、降雨型滑坡稳定性评价以及降雨型滑坡治理效果等方面进行了深入研究。主要取得的研究成果如下：(1)首先系统地分析了我国降雨型滑坡的空间分布特点、时间分布特点和降雨型滑坡的类型。然后以湖北省降雨型滑坡为研究对象，重点地研究了降雨型滑坡的时空分布特征和与之密切相关的降雨因子的时空分布规律，揭示了降雨型滑坡与降雨因子的一些关系。这对降雨型滑坡的评价和防治有着重要的意义。(2)分析了地下渗流对滑坡稳定影响的机理、降雨入渗对滑坡稳定影响的机理及其降雨因子(降雨量、降雨强度、降雨历时、降雨型式)对滑坡稳定性的影响。(3)系统地分析了渗流场的基本概念、基本定律、基本方程及定界条件。建立了降雨型边坡稳定性的渗流有限元分析模型，给出了降雨入渗有限元的实施步骤，结合实例，计算了不同降雨强度和不同降雨持时以及不同的渗透系数下雨后坡体内孔隙水压力变化趋势，探讨了上述参数变化对降雨滑坡渗流的影响。(4)建立了一个基于拉格朗日有限元法的降雨型滑坡过程的动态模型，该模型采用了Voellmy流变关系。以一降雨型滑坡为实例进行分析，模拟重现了由降雨所引起的边坡滑坡的动态破坏过程，模拟计算结果与实际结果吻合较好。(5)介绍了考虑孔隙水压力影响的滑坡稳定性分析方法及降雨作用下的滑坡稳定性分析方法；结合非饱和抗剪强度公式，对传统极限平衡分析法进行了改进，将孔隙水压力引入基于非饱和土抗剪强度理论的稳定性计算中，得到了改进后简布条分法的稳定性系数计算公式，并结合实例尽进行了详细地分析。(6)以模糊数学理论为基础，除考虑常规滑坡稳定性模糊评价模型所考虑的影响因子外，还考虑了降雨因子(包括降雨强度、降雨历时、累积降雨量、降雨型式等)，从而建立了降雨型滑坡稳定性的模糊综合评价方法，并结合实例阐述该方法的应用。(7)针对降雨滑坡的破坏往往是突发性的特点，以突变理论为基础，建立了降雨型滑坡稳定尖点突变模型，根据岩土体含水量与岩土体的性质指标关系，就可根据降雨型滑坡稳定尖点突变模型求得降雨型滑坡发生失稳时的体积含水量，然后再根据降雨入渗对岩土体重度γ、内聚力c和内摩擦角φ的影响，对降雨型滑坡破坏进行评价与预测。(8)对于降雨型滑坡治理方案的确定，决策者往往广泛征求研究、设计、勘察和施工等多个部门的专家的意见，但由于各位专家的偏好不尽相同，因此各专家对治理方案的评判不完全一致，这就必将给决策者带来决策上的困难。降雨型滑坡治理决策显然是一个群决策问题。针对降雨型滑坡治理方案评价是一个群决策问题，提出了降雨型滑坡治理群决策的二维足码定位法。此法利用简单的二维足码坐标图或评价涵数，就可以定出降雨型滑坡治理的最优决策方案。以一降雨型滑坡体治理实例分析了该方法的实际应用。(9)降雨型滑坡治理方案选择过程中所要考虑的指标(属性)错综复杂，有些指标很难精确化，通常不能提供这些指标的准确值，即评价指标的不完备性，同时不同专家对方案有偏好，所以，降雨型滑坡治理方案的选择应是一个对方案有偏好的属性权重信息不能完全确知的多属性决策问题。为了处理这种决策问题，提出了一种基于相似度的对方案有偏好的降雨型滑坡治理的三角模糊数型多属性决策方法。该方法首先建立一个线性规划模型，通过求解该模型获得属性权重，然后，基于三角模糊数两两比较的可能度公式及互补判断矩阵的排序公式，对降雨型滑坡治理方案进行优化决策。以一降雨型滑坡体治理实例分析了该方法的实际应用。(10)以溪沟口降雨型滑坡治理为研究对象，建立了降雨型滑坡治理效果分析的弹塑性有限元模型，对溪沟口滑坡治理前后的各种工况进行了数值模拟计算，得到了溪沟口滑坡治理前后各种工况下的等效塑性应变分布图、剪应力分布图、位移矢量分布图和溪沟口滑坡治理前后的稳定性系数。计算结果表明：①溪沟口滑坡治理后在天然状态下稳定性系数达到了1.32，达到了溪沟口滑坡防治安全等级的设计要求；溪沟口滑坡治理后在最不利情况(天然状态+暴雨+地震)下稳定性系数也达到了1.11，达到了溪沟口滑坡防治安全等级的设计校核工况要求。②溪沟口滑坡治理后的塑性区、剪应力和位移变化得了大大的改善。所以，溪沟口滑坡治理效果显著，治理方案设计达到了稳定安全要求。更多还原

【Abstract】 Landslides are serious unstable phenomenon of natural rock mass, and those caused by rainfall is defined as rainfall-induced landslides. Although the causation of landslides of cause includes the inter conditions, such as unfavorable geology, the structure of rock mass and so on, for the other hand, the impact of outside forces are also besides in it. There are quantities of outside forces that can lead to landslide, but undoubtly, among those factors, rainfall especially intensive rain or heavy rain is one of the most important factors. It triggers off landslides, which can be mainly described as below: during the rain, the surface water immerged into the rock mass, which increases the weight of the slope and the pore-water pressure. As a result, the slope turns into the limiting state of equilibrium, and begins to slide. With the rainwater keeps immerging, it breaks into the underground and converts into groundwater, which will emolliate the slope surface and decreases the shearing strength of it. Provided the hypsography and the geology necessary, rainfall will play a vital role in the factors that leads to landslides, as shown in a study. Many experts have made many effective explorations to the relationship between rainfall and landslide both here and abroad. They take different kinds of methods or models to find out the critical value of the raininess or the duration of the rain when landslides took place. With these work, they explain the relationship between rainfall and landslide to some degree, discuss the effects on the slope caused by rainfall from different angles, which laid a better groundwork for the further study of rainfall-induced landslides. Based on the returns of the predecessors, this text collects perennial historical data of the landslides and the rainfall in certain regions. By applying lots of theories, such as system approach, quantification theory, filtration theory and numerical analysis method, the text makes a deep research at many aspects of rainfall-induced landslides, including the feature, the process and the process control, the estimation of stability and the treatment effects of it. The mainly returns are as following:(1) Systematically analyzed the type, the spatial and the time distribution characteristic of rainfall-induced landslides. Then took the rainfall-induced landslides of Hubei Province as the research target; with concentrating on the space and time distribution characteristic of rainfall-induced landslides and the rainfall-factors that closely connected to it, it promulgated some relational rules between them.(2) Analyzed the way that underseepage, rainfall infiltration and the rainfall-factors (includes rainfall, rainfall intensity, rainfall duration, and rainfall pattern) influenced the salability of the landslides.(3) Analyzed the basic concepts, fundamental theories, fundamental equations, and delimitation conditions of the influent fields systematically. Inferred the fundamental formulas and the implementation step of the influent elements in the analysis of the stability of the rainfall landslides, which would provide the basis theory for the further analysis of the influent problems in rainfall-landslides.(4) Established a dynamic model for rainfall-induced landslides based on Lagrange finite element method, and Voellmy rheology was adopted. A practical case of a rainfall-induced landslide was analyzed. Through reproducing the dynamic runout process caused by the landslide, we get a simulated computation result, which fits the actual result well.(5) Introduced a method for computing the stability of the landslides that had been considered the influence of pore-water or rainfall. Combined with the non-saturated shearing strength formula, we made some improvements to the traditional limiting state of equilibrium analytic method, that is to say: the pore-water pressure is imported to the stability computation based on the non-saturated soil theory. In this way, we can get the formula used to compute the stability factor. And we had made a detail description with an example.(6) Based on the fuzzy mathematics theory, and not only considering the influence factors needed in the fuzzy appraisal model of the stability of the convention landslide, but also the rainfall-factors (includes rainfall, rainfall intensity, rainfall duration, and rainfall pattern), we established a fuzzy synthesis appraisal method for computing the stability of rainfall-induced landslides, and some examples are taken to describe the application of it.(7) According to the sudden characteristic of the destruction of rainfall-induce landslides, we established a cusp catastrophe model based on catastrophe theory. With this model, we computed the water content when the slope slides, according to the relationship between water content and rock mass. Then we made a conjecture and a forecast for the destruction according to the impaction on the unit weight, the cohesive force and the inner friction angle caused by rainfall.(8) Directed against the assessment slope treatment schemes being a problem of group decision making, a two-dimension leg-mark selected location method of group decision making of slope treatment is presented. In this method, the simple two-dimension leg-mark coordinate figure or assessment function is used, and the optimal scheme of the decision of slope treatment can be determined. The method is applied to the decision of Erzhong landslide treatment, and its application is discussed in detail.(9) The treatment engineering of landslide hazard is a complex systems engineering. The selection of its treatment schemes is depended on many factors such as technology, economics, environment, and risk. Policymakers have preference information on alternatives, and the attribute weight information is incomplete. To cope with such decision-making question with incomplete and preference information, a similarity degree-based method for triangular fuzzy number multi-attribute with preference information on alternatives is proposed. By using the method, a linear programming model is established firstly, and the attribute weights are derived by solving this model, then, based on a possibility degree formula for comparing two triangular fuzzy numbers and a formula for priorities of complementary judgment matrix, a priority method for alternatives is presented. Finally, the method is applied to the decision-making of Zhafangping landslide in the Three Gorge reservoir area, and a good result is gained, which show that the method is feasible and effective.(10) It had established elastic-plastic finite element matrix of effect analysis of treatment of rainfall-induced landslides of Xigoukou by using the treatment of rainfall-induced landslides of Xigoukou as the vestigated subject, and numerical simulated all operating modes of the course of it, the outcome was the equivalent plasticity strain distribution diagram, sheafing stress distribution diagram, and displacement pharos distribution diagram and stability coefficients of the course of the treatment in all operating modes. The calculation results showed that:①After the treatments, the stability factor of Xigoukou slope was as high as 1.32 in the nature state, which is adherence to the specification; and in the most disadvantage situation (nature state+rainstorm+earthquake), the stability facto also came to 1.11, and this was acceptable according to the safe class.②After treatment, the plastic zone, shearing stress and the range ability of displacement was greatly improved. Therefore, the effect of the treatment was remarkable, and the government plan meets the stable security requirements well.更多还原