【作者】 龙建辉；

【导师】 杜东菊；

【作者基本信息】 长安大学 ， 地质工程， 2008， 博士

【摘要】 针对高速远程黄土滑坡频繁发生的现实,在目前经济和技术条件还不足以彻底治理的情况下,开展对滑坡灾害的预测预报研究具有重要的现实和理论意义,也是当前国际上滑坡灾害研究的热点和难点问题。本文在已有研究的基础上,以陕西关中盆地滑坡灾害最为严重的滑坡带之一—泾阳县泾河南塬高速远程黄土滑坡带为研究对象,通过对滑带土特征强度参数的试验分析,运用统计模型、运动学模型、以及蠕变模型等,对泾阳南塬高速远程黄土滑坡的强度特性和时空预测预报方法进行了系统的研究。获得以下几个方面的成果:(1)滑带土在高速远程黄土滑坡的形成和发育规模等方面具有控制性作用。本文运用多种试验方法,从滑带土的峰值强度、残余强度、软化强度、长期强度和启动强度五个层面,对滑带土的抗剪强度特性进行了综合研究,提出了“属性强度”和“状态强度”的概念,论证了滑坡各特征强度的属性问题及其相互关系;认为:滑坡的峰值抗剪强度是一种“状态强度”,它与非饱和黄土的结构强度及含水量等因素有关;滑坡的完全软化强度和残余抗剪强度是一种“属性强度”,它主要与表征滑带土属性的粘粒含量、矿物成分及塑性指数等指标有关,并建立了属性强度与各属性间的相关关系,通过它们能较好地利用常规测试指标来获得抗剪强度。对滑带土微观结构的研究分析(SEM),验证了所得滑带土强度规律性的认识。(2)提出了滑坡“启动含水量”的概念。黄土滑带土的峰值强度特性表现为在一定的低含水量范围内,随含水量的增高强度降低较为缓慢,当达到一定含水量时,随含水量的增加强度骤降,滑坡获得高速启动的条件,它所对应的峰值抗剪强度就为滑坡的启动强度;测试与反演分析表明泾阳滑坡滑带土的塑限含水量为滑坡启动含水量。在此基础上分析了泾阳地区滑坡高速远程的力学机理,为强度骤降高速启动、滑带液化、以及“滚轴效应”等的综合反映。(3)在滑坡的空间预测方法上,通过对泾阳南塬黄土滑坡带的实地测量,得到了滑坡滑动前后的各项特征参数;建立了基于特征参数的高速远程黄土滑坡滑距预测的一元和多元统计模型;论证了Scheidegger公式和森胁·宽公式在本质上都为“架空坡(”H/L)理论,它在黄土地区的预测结果也具有很好的线性相关性,并得到了适合泾阳地区的修正模型。(4)建立了两个基于功能守恒和考虑滑带土强度参数及滑动液化的运动学模型:基于能量守恒、考虑滑坡运动特点和滑带土强度特性的滑距预测简化运动学模型,该模型充分考虑了滑坡运动阶段的强度特性,给出了具体的计算公式和预测方法;考虑滑动过程孔隙水压力影响和滑带液化,在前人提出的速度和滑距预测公式基础上,得到了其修正的预测方程。(5)对滑带土的蠕变特性进行了研究,建立了该区滑带土的蠕变经验方程,探讨黄土蠕变特性与滑坡失稳之间的内在联系,探索Saito模型在黄土滑坡时间预报方面的可行性,并提出了一种基于蠕变理论的滑坡时间预报估算方法。更多还原

【Abstract】 In view of the reality that the loess landslides with high speed and long-run distance occurred frequently, it is of very important significance to develop the forecasting research of landslide disaster in theory and in practice, under the present economic and technical conditions that they couldn’t been controlled thoroughly, which is also a focus and difficulty issue in the world. Based on the previous researches, taking the high-speed and long-run-distance loess landslides belt—one of the most serious landslide disaster belts in Guanzhong basin of shaanxi province—which lies on the south bank of Jinghe River in Jingyang County as research object, this paper studied the strength characteristics of the loess landslides with high speed and long-run distance through the experimental analysis of slide soil, and researched the spatiotemporal forecast methods systematically by adopting statistical model, kinematical model and creep model. Some achievements obtained are in the following several aspects:(1) The slide belt soil is of the control effect in forming, developing and scale of the high-speed and long-run-distance loess landslides. Many kinds of testing methods and research tools were used to study synthetically the shear strength characteristics of the slide zone soil on 5 aspects such as peak strength, residual strength, softening strength, long-term strength, and starting strength.“Property strength”and“state strength”are newly proposed in the paper to explain their properties of all strength characteristic parameters of loess landslide and their relationship, the author in the paper considers that: the peak shear strength is a kind of“state strength”, correlating mainly with the loess’s structural strength and water content of non-saturated loess. Residual strength and softening strength are both kind of“property strength”, which is mainly related to soil property index , such as the clay content, the mineral component and the plasticity index and so on, and some correlations are established among them through which shear strength could be better obtained by adopting the conventional test indexes. A result of the microscopic structure’s research analysis (by SEM) to the slide zone soil has confirmed the acquaintanceship obtained.(2) Proposed the concept of“starting water content”of landslide. The slide zone loess’s peak strength displays the characteristics that its strength, in certain lower water content scope, reduces slowly along with the water content’s increasing; and plummets rapidly along with the water content’s increasing when water content reaches a certain point. Which can explain that landslide obtains the condition of high-speed starting; its corresponding peak shear strength is the landslide’s starting strength. The test and back analysis indicates the plastic limit water content of the Jingyang landslides’slide soil is the starting water content of them. Based on concept of“starting water content”of landslide, the paper analysis the mechanics mechanism of the loess landslides with high speed and long-run distance in Jingyang area, which is a kind of synthesis reflection of the strength’s plummeting rapidly to cause high speed starting, the slide zone’s liquefication, as well as the“roller effect”and so on.(3) As to landslide space forecasting, through the surveying on Jingyang south plateau loess landslide belt on the spot, each characteristic parameter before or after slope sliding is obtained. One-dimensional or multi-dimensional statistical model of the sliding distance of loess landslide with high -speed and long-run distance are established based on the characteristic parameters; the Scheidegger forecasting formula and the Xiesong K. forecasting formula are proved the same theory built on the“stilts slope”(H/L) essentially, they also have a fine linear relativity forecasting result in the loess area’s, and its modified forecasting model is obtained.(4) Paper has established two kinematics models based on the function conservation and considered of the slide zone soil strength parameters: One of them is a simplified kinematics forecasting model based on the energy conservation, the consideration of characteristic landslide movement and the strength property of slide zone soil, this model fully considers the strength property during the moving of landslide, the concrete formula and the forecast technique are provided. Another considers the influence of pore-water pressure during sliding and of the slide zone’s liquefaction; based on the speed and slips in the prognostic formula proposed in the predecessor; the modified forecast equation is obtained.(5) Conducted the research on creep property of the slide zone soil, and established slide zone soil creep empirical equation in this area, discussed the inner link between loess creep property and the landslide jitter, explored the feasibility of Saito model in the loess slope time forecasting, and proposed one estimate method of landslide time forecast based on the creep theory.更多还原