黄土台塬滑坡水文地质结构探测及失效成因分析  

Hydrogeological structure exploration and failure cause analysis of landslide in loess tableland

作　　者：沈永东 邱海军[1,2,3] 胡胜 刘子敬[1,2] 张焱 杨冬冬 曹明明 Shen Yongdong;Qiu Haijun;Hu Sheng;Liu Zijing;Zhang Yan;Yang Dongdong;Cao Mingming(College of Urban and Environmental Sciences,Northwest University,Xi'an 710127,Shaanxi;Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity,Northwest University,Xi'an 710127,Shaanxi;Institute of Earth Surface System and Hazards,Northwest University,Xi'an 710127,Shaanxi)

机构地区：[1]西北大学城市与环境学院,陕西西安710127 [2]陕西省地表系统与环境承载力重点实验室,陕西西安710127 [3]西北大学地表系统与灾害研究院,陕西西安710127

出　　处：《第四纪研究》2019年第6期1503-1513,共11页Quaternary Sciences

基　　金：科技部第二次青藏高原综合科学考察研究项目(批准号:2019QZKK0903);国家重点研究发展计划政府间国际创新合作专项项目(批准号:2018YFE0100100);国家自然科学基金项目(批准号:41771539)共同资助。

摘　　要：以陕西省合阳县北郭村滑坡为例,利用电阻率成像技术分别对台塬内部、滑坡后缘及滑坡体的水文地质结构进行了探测,并结合野外地面调查对结果进行了分析与验证。结果表明:1)台塬内部地下水位起伏较大,受地形因素影响向塬边运动;滑坡后缘地下水沿侵蚀沟和滑坡方向运动,地下水位最浅约在3 m以下;滑坡体地下水运动方向大致与滑动方向一致,地下水位最浅约在坡面5 m以下,黄土含水率很高,坡体极不稳定。2)台塬内紧邻东西两侧侵蚀沟的区域与塬体间存在裂缝或发育空洞;滑坡后缘侵蚀沟分布的串珠状落水洞在物探剖面上整体电阻率偏高,侵蚀沟顶部区域与塬体间存在深约34 m的裂缝或空洞。3)诱发滑坡产生的因素有3个:滑坡后缘串珠状分布的落水洞和物探发现的裂缝或发育空洞是后缘失稳的构造因素;灌溉水入渗汇入地下水向塬边运动导致塬内到塬边斜坡体方向的地下水位抬升,在滑坡体地下深层和坡脚基底形成饱水黄土软弱层是斜坡失稳的另一个因素;坡脚基底因长期受荷塘水浸没加剧了滑坡发生的可能。The Loess Plateau is a frequent occurrence area of geological disasters in China,in which the loess table area is about 32000 km2,accounting for 5.7%of the area of the Loess Plateau.Due to unreasonable agricultural irrigation and slope excavation by local residents,large-scale loess landslides or landslides have been triggered.The traditional investigation method is difficult to detect the hydrogeological structure of landslide area effectively.The traditional survey method is difficult to effectively detect the hydrogeological structure of the landslide area.Therefore,this paper takes the landslide of Beiguo Village landslide(35°01'24"N,110°15'07"E)in Heyang County,Shaanxi Province as an example,and used resistivity imaging technology to explore the hydrogeological structure of the tableland,the back edge of the landslide and the landslide body,and verified the results based on field ground investigation.The results show that:(1)The groundwater level in the tableland fluctuates greatly and moves to the edge of the tableland under the influence of topographic factors;the groundwater in the rear edge of the landslide moves along the erosion ditch and the direction of the landslide,the groundwater level is the shallowest below 3 m.The groundwater movement of the landslide body is roughly the same as the sliding direction.The groundwater level is the shallowest about 5 meters below the slope.The loess has a high water content,so the slope is extremely unstable.(2)Cracks or developed cavities exist between the middle area of the west and west erosion ditch and the plateau,and the overall electrical resistance of sinkholes distributed on the rear edge of the landslide is on the high side of the geophysical section;and there are cracks or voids about 34 m deep between the top area of the erosion gullies and the tableland.(3)There are three factors that induce landslides:The sinkhole distributed on the rear edge of landslide and the cracks or developmental voids found by geophysical exploration are the structural fact

关 键 词：电阻率成像技术 水文地质结构 黄土台塬 滑坡 灌溉 

分 类 号：P642[天文地球—工程地质学]