【作者】 罗东海；

【导师】 王念秦；

【作者基本信息】 西安科技大学 ， 地质工程， 2010， 硕士

【摘要】 “西部大开发”战略举措不断深入,黄土山地逐步被广泛开发利用,作为脆弱黄土地区负效应的黄土滑坡灾害与日俱增,严重制约了该地区的良性发展,为此,黄土滑坡灾害研究日益受到重视,但灾害机理仍是国际难题,深入研究具有重要的理论意义、经济意义和社会意义。选择冻融期黄土滑坡为研究对象,综合运用地学、数学、力学及系统科学相关理论,利用系统调查、广泛资料归纳、数值模拟、1m地温测试、模糊分析、层次分析等方法,以水的作用为主线,对冻融期黄土滑坡滑坡区地下水分布、温度场特征、形成机理解释及发育阶段判定等方面进行了有益探讨。主要结论如下:(1)以“1m地温理论”为指导,选择会宁县太平乡某冻融期黄土滑坡为实例,通过1m地温监测,编绘“滑坡区地下水水脉分布图”,探索冻融期黄土滑坡区地下水分布规律;(2)ADINA-T模拟结果“当外界温度为0℃时,坡体温度场由坡表到坡底,温度基本逐渐增加,但到一定深度后,温度基本保持不变;冻结时间1个月时,外界温度为-10℃时,冻深约为0.95m;当冻结时间2个月时,外界温度为-15℃,冻深约为1.15m;当冻结时间3个月时,外界温度为-20℃,达到最低温度,冻深约为1.35m,达到最大冻深。”与理论推导和实测最大冻结深度比较吻合。(3)建立了“冻结前后滑坡区地下水运移模型”,以黄土地区分布最为广泛的滑坡类型——黄土泥岩顺层滑坡为模型,采用水文学原理,在确定边界条件和一定假定条件基础上,推导出浸润线方程;并分析了冻结后地下水浸润线分布情况。(4)“冻结滞水促滑效应”主要表现为:冻结层虽阻碍了坡表径流下渗,但也堵塞了地下水排泄通道,使坡体成为一“储水囊”,地下水分布范围不断扩大、水位不断上升,增大了滑坡区动、静水压力,降低了斜坡,尤其是滑动面附近岩土体强度,进而加速斜坡变形甚至诱发滑坡灾害。以洒勒山滑坡为例,说明冻融作用是其主要作用因素和诱发因素;以会宁县太平乡滑坡为例,计算了冻结前后滑坡稳定性,结果表明冻融作用对滑坡稳定性影响较大。(5)采用可能度区间判断矩阵排序法的“改进可拓层次分析法”,既考虑了人类对事物判断的模糊性特点,又可避免传统层次分析法的大量试算工作。建立了“滑坡时间预报可拓层次分析模型”,利用改进可拓层次分析法,可通过滑坡宏观迹象调查判定滑坡发育阶段。本研究成果,有益于判定黄土地区斜坡地下水分布规律,能较好解释冻融期黄土滑坡灾害频繁现象,丰富了滑坡滑动机理及预测预报理论,对黄土滑坡防治方案决策和工程布置有一定参考意义。更多还原

【Abstract】 With the "Western Development" strategy continuing to deepen, loess area is widely development and utilization gradually, as a weak negative effect of the loess area, loess landslide hazard grow day by day, and seriously hamper the development. Loess landslide research has received increasing attention, but the disaster mechanism remains a major international problem, in-depth study has important theoretical significance, economic significance and social significance.Select freezing-thawing period of loess landslide as the research object, use geography, mathematics, mechanics and systems science-related theories, use systematic investigation, extensive information on induction, numerical simulation, 1m ground temperature test, fuzzy analysis, hierarchical analysis methods, do beneficial aspects to loess landslide mechanism of freezing-thawing period, finding the development rule of groundwater and time prediction of loess landside. The main conclusions are as follows:(1) Introduction of Japanese decline and groundwater experts, Dr Atsushi Takeuchi proposed "1m geothermal theory", using the theory can establish "1m ground temperature distribution" and "Location of underground water veins," and further analysis of horizontal distribution of groundwater decline, study the location and size of underground water veins.(2)ADINA-T simulation results:When the outside temperature is 0℃, the temperature gradient gradually increased from the slope surface to the base, but to a certain depth, the temperature has remained unchanged. when the freezing time is 1 month, the outside temperature is -10℃, the freezing depth is about 0.95m. When the freezing time is the 2 months, the outside temperature is -15℃, the freezing depth is about 1.15m.When the freezing time is about 3 months, the outside temperature is -20℃, the freezing depth is about 1.35m, arrive maximum depth. The maximum depth of theoretical derivation is anastomosised for the measured.(3) Establishing of "a groundwater transporting model of landslide before and after the freezing", using the loess landslide types of loess-mudstone planar landslide which is widest distribution as landslide model, using principles of hydrology on the base of determining the conditions and boundary conditions assumed, derived the basic differential equation saturation line; and analysis of frozen ground water seepage line distribution.(4) The feature of " effect of promoting slip by frozen perched water" are as follows: Hamper the runoff infiltration, but also blocked the groundwater discharge channels, the slope become as a "storage bladders," expanding the scope of the distribution of groundwater, rising the water level, increasing dynamic and hydrostatic pressure of landslide area, reducing the slope in particular the strength of rock and soil mass, speed up the slope deformation and even induced landslide hazard.Take Saleshan landside as an example,analyze the causes of the landside,thought that the freezing-thawing affect is the mian contributing factors and triggers;Take the Huining County Taiping landside as an example,the calculation of the stability of freezing before and after,the results show that the role of freezing-thawing is greater to the stability.(5) Using "Improving the extension of AHP," take into account both the human right to determine the fuzzy character of things, but also to avoid the traditional analytic hierarchy process a large number of spreadsheet work. Established a "slippery slope time prediction of extension AHP model", the use of improved extension of AHP, the macro can be signs of landslide investigation had determined that landslide developmental stages.In this paper, the results can be better explained the frequent loess landslide phenomenon of freezing and thawing period, enrich the time of landslide prediction theory, help determine the distribution of loess area of groundwater, have a certain reference to loess landslide prevention programs and decision-making.更多还原