长期干旱背景下降雨型松散堆积体滑坡机理研究

发布时间：2018-05-02 11:48

本文选题：长期干旱 + 模型试验　；参考：《长安大学》2015年硕士论文

【摘要】：降雨条件下滑坡产生的机理及相应评价方法的研究成为近年来岩土工程界越来越关注的课题。近几年,由于极端气候的出现越来越频繁,全球干旱和强降雨交替的现象频频出现。针对我国大范围长期干旱—强降雨交替出现的气候特点,松散堆积体边坡岩土体工程特性的劣化,包括抗剪强度和渗流特性的改变。本文基于现场监测、模型试验和数值分析方法,研究了松散堆积体边坡在此环境下的破坏机理。首先利用室内模型试验分析研究了经历长期干旱的边坡和未经历干旱的边坡在相同降雨条件下坡体位移、坡体内部土压力以及孔隙水压力等值的变化情况。再利用GeoStudio软件建立数值模型模拟边坡失稳破坏的整个过程,通过SEEP/W和SLOPE/W对坡内渗流和坡体稳定性进行分析,比较了相同降雨历时和降雨强度下长期干旱边坡和表层无干旱边坡土体内部水分渗流过程和坡体稳定性的变化,对比分析数值模拟与模型试验的结果,揭示边坡破坏的机理。模型试验及数值分析结果表明:1)模型试验中,随着降雨的持续进行,坡内土压力和孔隙水压力处于不断变化中。2)相同降雨条件下长期干旱边坡较未经历干旱边坡更易发生沉降和整体移动。经历过长期干旱的松散体边坡受降雨影响更为显著,降雨更易于入渗。3)由数值模拟得出,随着降雨的进行,坡体安全系数持续减小,相应的边坡稳定性也持续减小。降雨结束后,坡体安全系数逐渐升高,最后基本趋于稳定。而长期干旱边坡稳定系数始终低于表层无干旱边坡的稳定系数。该研究结果为长期干旱—强降雨条件下的此类边坡的设计和治理提供依据,对工程建设影响范围内的松散堆积体边坡的设计和灾害防治具有直接的工程指导意义。
[Abstract]:In recent years, more and more attention has been paid to the mechanism and evaluation methods of landslide under rainfall conditions. In recent years, due to the occurrence of more and more extreme climate, the phenomenon of global drought and heavy rainfall alternates frequently. In view of the climatic characteristics of long-term drought and heavy rainfall in China, the deterioration of engineering characteristics of rock and soil mass of loose accumulative body slope, including the change of shear strength and seepage characteristic, is discussed in this paper. Based on field monitoring, model test and numerical analysis, the failure mechanism of loose accumulative slope in this environment is studied in this paper. First, the changes of slope body displacement, soil pressure and pore water pressure under the same rainfall conditions were studied by indoor model test. The whole process of slope failure is simulated by using GeoStudio software. The seepage and stability of slope are analyzed by SEEP/W and SLOPE/W. The process of water seepage and the stability of slope body in long term arid slope and surface arid slope were compared under the same rainfall duration and rainfall intensity. The results of numerical simulation and model test were compared and the failure mechanism of slope was revealed. The results of model test and numerical analysis show that in the model test, with the continuous rainfall, The soil pressure and pore water pressure in the slope are constantly changing. 2) under the same rainfall conditions, the long-term arid slope is more prone to settlement and overall movement than the non-experienced drought slope. The results of numerical simulation show that the slope safety factor decreases continuously and the slope stability decreases with the rainfall. After the rainfall, the slope safety coefficient gradually increased, and finally tended to be stable. The stability coefficient of long-term arid slope is always lower than that of non-arid surface slope. The results provide the basis for the design and treatment of this kind of slope under the condition of long-term arid and heavy rainfall, and have direct engineering guidance significance for the design and disaster prevention of loose accumulative slope in the scope of engineering construction.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.22

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