水库施工期间坝前滑坡稳定性研究

为了更好地研究水库建设阶段的坝前滑坡问题,以甘肃省九甸峡库区燕子坪滑坡为例,采用GPS对库岸滑坡表面的位移和变形进行了高精度、连续性监测,完成了水库建设阶段的滑坡演化全过程的位移变化监测。结合滑坡区的工程地质条件,对滑坡的变形特征、诱发因素及形成机理进行了分析,从力学变形机制方面研究施工期坝前滑坡诱发机理。结果表明:水库施工期坝前滑坡失稳分为两个阶段(施工围堰建成前后),并且两个阶段坝前滑坡失稳主要影响因素不同;施工围堰建成前坝前滑坡主要是在受降雨影响,施工围堰建成后库水位上升是坝前滑坡失稳的主要诱因,整个施工期间施工围堰建成后的滑坡变形占较大比重,并且两个阶段滑坡失稳形式均表现为中、后部推移前缘滑动。

Study on the stability of landslide in front of dam during reservoir construction

In order to study the landslide in front of dam during reservoir construction，Yanziping Landslide occurred in the area of Jiudianxia Reservoir in Gansu Province is taken as the study case，and then the monitoring on the overall changing process of the displacement for the landslide evolution during the construction of the reservoir is completed with a high accuracy and continuous monitoring made on the surface displacement and deformation of the reservoir bank with GPS. Combined with the engineering geological condition of the landslide area，the deformation characteristics，the inducing factors and the forming mechanism of the landslide are analyzed，furthermore，the inducing mechanism of the landslide in front of the dam during the construction is studied from the aspect of the mechanism of the mechanical deformation as well. The results show that the landslide-instability in front of the dam during the construction of the reservoir is divided into two phases （before and after the construction of the construction cofferdam），moreover，the main factors of the impacts on the landslide-instability in front of the dam in both the phases are different； i.e. before the construction of the cofferdam，the impact on the landslide deformation comes mainly from the rainfalls therein and the main inducing factor after the construction of the cofferdam is the rise of the water level，thus the landslide deformation after the construction of the construction cofferdam during the whole construction period is made up a larger proportion of the total. Moreover，the landslide-instability modes in both the phases show that the mid and rear parts push the fore-edge to be slided.