三峡库区滑坡堆积体非饱和土—水特征测试及渗流分析

发布时间：2018-03-28 01:27

本文选题：三峡库区　切入点：滑坡堆积体　出处：《成都理工大学》2017年硕士论文

【摘要】：滑坡堆积体在自然界广泛分布,在三峡库区尤为常见。堆积体物质岩性主要由残坡积、冲洪积、崩滑坡积等形成的砂砾石、碎石、块石的土石混合物组成。据统计,三峡库区涉水滑坡滑体多为不同类型的土石混合物所组成。土石混合物兼有碎石与土两者的相关力学特性,因此其同样具有非饱和土的特性,可以称作特殊的非饱和土。堆积体在降雨与库水位升降的过程中,坡体内物质会经历由干到湿,再由湿到干这样一个从非饱和到饱和,再由饱和到非饱和的过程。堆积体的渗流、稳定性与坡体的非饱和特性密切相关。因此,非饱和土石混合物的非饱和土-水特征研究及渗流分析对地质灾害防治与土木工程建设具有重要价值。主要工作及研究成果如下:1、首先对三峡库区堆积层滑坡滑体物质进行了详细统计分析,该区域内滑体为土石混合物的滑坡总计占比98%,而碎石含量在20%以上的滑坡占比87%,滑体主要由碎石土、块石土或粉质粘土夹(含)碎石、夹(含)块石组成。2、在对典型滑坡土-水特征试验基础上对室内试样进行分类,通过室内压力板仪试验取得了多条土-水特征曲线,重点分析了碎石粒径大小、碎石含量、颗粒级配、干密度以及土的塑性指数对土石混合物的土-水特征曲线的影响,得出碎石颗粒较小、碎石含量较大的土石混合物对土-水特征曲线的影响与干密度较小、土的塑性指数较小的土石混合物对土-水特征曲线有同一影响趋势。3、基于FredlundXing(FX3)模型,该模型中三个特征参数值随物质本身结构变化具有一定规律性;采用SPSS软件回归分析得出简便的计算三特征参数的方程;提出利用室内基本物理实验得到滑坡堆积体土-水特征曲线的方法,该方法具有一定实用性。4、通过典型滑坡现场基质吸力试验,得出现场土的土-水特征曲线,与采用公式计算所得曲线以及取样室内试验曲线进行对比分析,得出采用公式计算的土水特征曲线能够较好反应实际情况,同时也阐明了不同之处的原因。5、最后将公式预测所得土-水特征曲线应用于典型滑坡,通过数值模拟分析了其渗流场的变化特征。两个典型滑坡的地下水位线都存在不同程度的滞后现象。影响坡体地下水位线凹凸变化程度的主要因数为滑体物质的饱和渗透系数、非饱和渗透系数函数、坡面坡度以及渗流路径长度。
[Abstract]:Landslide deposits are widely distributed in nature, especially in the three Gorges Reservoir area. The material lithology of the accumulative body is mainly composed of sand gravel, gravel, rock masses and rock mixtures formed by residual slope deposits, alluvial deposits, landslide deposits, etc. According to statistics, The landslide landslide in the three Gorges Reservoir area is composed of different types of mixture of soil and rock. The mixture of soil and rock has the related mechanical properties of gravel and soil, so it also has the characteristics of unsaturated soil. It can be called special unsaturated soil. In the process of rainfall and reservoir water level rising and falling, the matter in the slope will go from dry to wet, and from wet to dry from unsaturated to saturated. The seepage and stability of the accumulation body are closely related to the unsaturated characteristics of the slope body. The study on unsaturated soil-water characteristics and seepage analysis of unsaturated soil-rock mixture is of great value for geological hazard prevention and civil engineering construction. The main work and research results are as follows: 1. Firstly, the landslide slide of the accumulation layer in the three Gorges Reservoir area is studied. The body matter was analyzed in detail. In this area, the total proportion of landslides with earth-rock mixture is 98%, while that of landslide with more than 20% gravel content is 87%. The slide body is mainly crushed with crushed stone, massive stone or silty clay. On the basis of the typical landslide soil-water characteristic test, the indoor samples are classified, and many soil-water characteristic curves are obtained through the indoor pressure plate test. The grain-size of the crushed stone and the content of the crushed stone are analyzed emphatically. The effects of particle gradation, dry density and soil plasticity index on soil-water characteristic curve of soil-rock mixture are obtained. The soil-rock mixture with small soil plasticity index has the same influence trend on soil-water characteristic curve. 3. Based on FredlundXingFX3 model, the three characteristic parameters of the model have certain regularity with the structure of the material itself. The equation of calculating the three characteristic parameters is obtained by SPSS regression analysis, and the method of obtaining the soil-water characteristic curve of landslide accumulation body by laboratory basic physical experiment is put forward. This method has some practicability. Through the field suction test of typical landslide, the soil-water characteristic curve of the field soil is obtained, which is compared with the curve calculated by the formula and the curve of the sampling laboratory test. It is concluded that the soil-water characteristic curve calculated by the formula can better reflect the actual situation, and at the same time, the reasons for the difference are clarified. Finally, the soil-water characteristic curve predicted by the formula is applied to the typical landslide. The variation characteristics of seepage field are analyzed by numerical simulation. The underground water level lines of two typical landslides have different degrees of hysteresis. The main factor that affects the variation degree of subsurface water level line of slope body is the saturation permeability coefficient of sliding material. Unsaturated permeability coefficient function, slope and length of seepage path.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.22

【相似文献】