伊犁谷地黄土滑坡发育分布规律及成因

The development and distribution of loess landslides in Yili Valley and its causes

在前人研究基础上,通过现场调查分析黄土滑坡地质条件及发育特征,进一步统计分析伊犁谷地23处典型黄土滑坡形态及滑床、滑体等要素。结果发现,该区降水量及次数与滑坡发生频次正相关,多发生在春夏之交和夏季,集中在4—9月;滑坡主要发育在河谷南北两侧中低山及低山丘陵地带,1300~2000 m高程上最集中;具环河平原带状分布特征,沟谷和交通沿线较发育;山区滑坡类型中以黄土型为典型。伊犁谷地黄土滑坡发生机制为“大气降水+冰雪融水→地表水下渗→坡脚侵蚀→冻融循环→累积性破坏→坡体湿陷、蠕变→坡体突滑”多因素影响下,长达约20年的前期蠕变到2小时快速滑动的过程。

Based on previous studies,the authors and other researchers analyzed the geological conditions and development characteristics of loess landslides through on-site key investigations,and further statistically analyzed 23 typical loess landslide shapes,slide beds and sliding bodies in Yili Valley.It was found that the amount and frequency of precipitation in this area were positively correlated with the frequency of landslides,which mostly occurred between the spring and summer and summer,concentrated from April to September;landslides were mainly developed in the middle and low mountains and low mountain hills on the north and south sides of the valley.It is most concentrated at an elevation of 1300~2000m;it has a belt-like distribution characteristic around the river plain,with more developed valleys and transportation;the loess type is the most typical of mountainous landslide types.Studies have shown that the occurrence mechanism of loess landslides in the Ili Valley is"atmospheric precipitation+ice and snow melt→surface water infiltration→slope foot erosion→freeze-thaw cycle→cumulative damage→slope collapse,creep→slope slippage".The process of creeping from several years to a few hours of early creep to rapid sliding.