灌溉引起地下水位上升对斜坡稳定性的影响——以甘肃黑方台为例  

Effect on Slope Stability due to Groundwater Rising Caused by Irrigation:A Case Study of Heifang Platform in Gansu,China

作　　者：谷天峰[1] 朱立峰[2] 胡炜[2] 王家鼎[1] 刘亚明[1] 冯力[1] 

机构地区：[1]西北大学地质学系大陆动力学国家重点实验室,陕西西安710069 [2]中国地质调查局西安地质调查中心,陕西西安710054

出　　处：《现代地质》2015年第2期408-413,共6页Geoscience

基　　金：国家自然科学青年基金项目(41202187);中国地质调查局项目(12120114025701)

摘　　要：灌溉诱发黄土滑坡是黄土高原地区一种常见的地质灾害,其实质是地下水位上升,引起黄土基质吸力下降,强度降低,最终导致黄土斜坡失稳的过程。以甘肃黑方台典型黄土斜坡为例,在非饱和土特性试验基础上,通过饱和-非饱和渗流分析,研究了地下水位上升引起的黄土斜坡内部渗流场的变化特征,探讨了地下水位变化对斜坡稳定性的影响。结果表明:地下水位上升,对斜坡内部孔压分布影响较大;地下水位上升,导致饱和区域增大,非饱和区基质吸力降低;斜坡内部基质吸力的降低与地下水位呈线性关系。以渗流分析为基础,对典型斜坡进行了极限平衡分析,结果表明,地下水位上升与稳定性系数下降基本上呈线性关系,在距离坡顶100 m位置的黄土层中地下水位约21 m时,边坡出现失稳。Irrigation-induced loess landslides are common geological disasters in the Loess Plateau region, and its essence is the groundwater rising which caused loess matric suction falling and intensity decreasing, eventually leading to the instability process of loess slope. In this paper, taking Heifang platform typical slope for example, we studied the variation of seepage field internal the loess slope which caused by the groundwater level rising, and investigated the affect that the groundwater level changes on slope stability, which both based on the charac- teristics test of unsaturated soil and the saturated-unsaturated seepage analysis. The results show that the groundwater level rises which has an obvious effect on pore pressure distribution internal slope and results in the saturation region increasing and matric suction reducing in unsaturated zone. There is a linear relationship be- tween decreasing of matric suction internal slope and groundwater level. We made unsaturated limit equilibrium analysis in the typical slope, based on seepage analysis. The results show that there is approximate linear rela- tionship between groundwater level rising and stability coefficient decreasing. Slope instability occurs, while groundwater level in loess layer of about 21 m, 100 m from the top of the hill.

关 键 词：灌溉 基质吸力 渗流场 斜坡 稳定性 

分 类 号：P642[天文地球—工程地质学]