甘肃永靖黑方台地区灌溉诱发作用与黄土滑坡响应

An analysis of the inducing effects of irrigation and the responses of loess landslides in Heifangtai area

黑方台地区自灌溉以来,诱发了大量的滑坡,但缺乏系统地对研究区的滑坡历史分析研究。在黑方台滑坡历史分析的基础上,研究灌溉引起的地下水位上升过程与滑坡的历史关系,对比分析不同时期的地下水位对滑坡稳定性、滑坡体积及后壁垮塌速度的影响。历史数据分析表明,灌溉引起的水位上升与滑坡发生的频率、体积存在明显的相关性,选取的典型滑坡稳定性计算结果显示滑坡具有多期逐级后退式特征,随着灌溉时间的增长,滑坡体积逐渐减小,但发生频率逐渐增大,基于DEM数据计算的滑坡变形也验证了计算结果。研究成果基本反演了灌溉引起的黄土滑坡历史过程,对黑方台滑坡的综合治理提供了数据支撑。

Since irrigation started in Heifangtai, a great number of landslides have occurred. However, there have been rare analyses of the landslide history in Heifangtai. In this paper, the landslide history in Heifangtai was analyzed. On such a basis, the relationship between the rising process of the groundwater table and the landslide history was studied, with the purpose of analyzing the impacts of the groundwater table of different periods on corresponding landslide stabilities, landslide volumes, and the failure velocities of the posterior walls. The analyses of historical data show that there is obvious dependency between the rise of groundwater table due to irrigation and the frequency and volume of landslide. The stability calculation results of selected typical landslides show that the landslides have multiple-phase retrogressive characteristics. With the increase of irrigation time, the volumes of landslides gradually decrease while the frequencies of occurrences gradually increase. The deformation results derived from DEM-based calculation also verify the calculation results. The results basically inverse the historical process of loess landslides induced by irrigation and provide data supports for the comprehensive prevention and control of Heifangtai landslides.