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2015年4月29日上午,甘肃省永靖县盐锅峡镇黑方台滑坡高频发区的党川村罗家坡同一斜坡处连续发生了2次大规模黄土滑坡,总体积约65×10~4m~3,最大滑距630 m,摧毁14户居民房屋和3家工厂.通过现场详细调查、取样试验、1∶500地形测量、滑坡影像、视频等资料分析,对灌溉引发的罗家坡黄土滑坡的特征、滑动过程、形成机理进行了探讨.结果表明:第1次滑坡经过近2 a变形过程,整体突然失稳,高速远程滑动;第2次滑坡变形时间仅3 h,分块逐步滑动,滑动历时长而过程复杂,总体为低速远程滑动.高陡的地形和强度低、水敏感性强的土体是滑坡发生的基础,黄土台塬区长期农业灌溉是引发因素,大量水体入渗形成了20余米厚的饱和软弱基座,使抗剪强度降低,导致斜坡失稳滑动.黄土滑坡高速远程滑动的主要原因是滑坡剪出口位置高,滑动势能大,释放条件好,剪出口下部陡坡段为主要加速段;前方有开阔的滑动空间且有一定坡度、平缓的滑道;滑体底部饱和软弱黏性土在滑道上持续产生超孔隙水压力、液化等低摩阻效应,是远程滑动的润滑剂.同时,两次滑体间还存在冲击加速和能量传递作用.
On the morning of April 29, 2015, two large-scale loess landslides occurred consecutively on the same slope of Luojiapo, Dangchuan Village, Heifangtai, Yanghuxia Town, Yongjing County, Gansu Province, with a total volume of about 65 × 10 ~ 4m ~ 3 , With a maximum sliding distance of 630 m, destroying 14 residential buildings and 3 factories.Through the field investigation, sampling test, 1: 500 topographic survey, landslide image and video data analysis, the characteristics of sloping The results show that the first landslide undergoes a sudden deformation over the past 2 years, and the whole landslides suddenly slide downwards at high speed. The second landslide deformation time is only 3 hours, and the blocks slide gradually and slide long The process is complex and the overall low-speed long-range slide.The steep terrain and low strength and water-sensitive soil is the basis of landslide, long-term agricultural irrigation in the Loess Plateau is the trigger factor, a large number of infiltration of water formed more than 20 meters Thick saturated weak base, the shear strength is reduced, leading to instability of slopes.The main reason of high-speed long-distance slide of loess landslide is that the location of exit of landslide shear is high, the sliding potential energy is large, release condition is good, To speed up the segment; there is an open sliding space in front and a certain gradient, smooth slide; slippery saturated soft cohesive soil at the bottom of the continuous production of excess pore water pressure, liquefaction and other low friction effect, the remote sliding lubrication At the same time, there are still two shocks between the acceleration and energy transfer role.