黄土特高边坡垮塌原因分析及综合整治措施

Analysis on Causes of Loess Extra High Slope Collapse and Comprehensive Improvement Measures

研究目的:黄土高边坡在地表水、地下水及隐形滑动面的作用下,极易发生溜坍或滑动。例如,陕北某黄土沟谷一挖方高边坡,其挖方边坡高度为110 m,为超高边坡且原始边坡中下部发育有大型古滑坡,2015年雨季持续降雨造成六级平台以下边坡发生坍塌,2016年雨季强降雨使边坡左、右两侧滑塌区范围进一步扩大,局部六级平台已全部垮塌,坍塌面局部延升至十二级平台边缘,整个黄土特高边坡处于极不稳定状态,本文旨在对该特高边坡垮塌原因进行分析并提出综合整治措施。研究结论:(1)查明了黄土超高边坡的地质结构及相应力学特性,采用瑞典圆弧法得到了边坡稳定性检算结果;(2)根据本边坡工程地下水补、径、排情况,得出了地下水对黄土边坡稳定性影响规律;(3)探明了原始边坡古滑坡分布范围和滑面埋深,找到了古滑坡和黄土边坡坍塌的内在关系及坍塌成因;(4)本黄土特高边坡高度超过了相关规范适用范围,但经过专门论证研究,采用设置竖向渗井、抗滑桩、挡土墙等综合整治措施,保证了边坡的稳定性;(5)本边坡综合治理设计及施工经验可为高大土质边坡、地下水丰富的边坡治理工程提供借鉴或参考。

Research purposes： Loess high slopes tend to slip or slide under the action of surface water,groundwater and invisible sliding surfaces. The project is located in a loess valley in the north of Shaanxi and the excavation slope height is 110 m. It is an ultra-high slope with large ancient landslides in the middle and lower part of the original slope. The continuous rainfall in the rainy season in 2015 resulted in the collapse of the slope below the six-level platform. In2016,the heavy rainfall in the rainy season further expanded the slopes collapse on the left and right sides of the slope.The six-level platform has completely collapsed and the collapsed surface partially extended to the edge of the platform of the twelve-level platform. The entire loess high slope is in an unstable state and requires comprehensive management.Research conclusions：（1） The geological structure and corresponding mechanical properties of the loess ultra-high slope were ascertained. The Swedish arc method was used to obtain the results of slope stability verification.（2） According to the groundwater recharge,runoff and drainage conditions of the slope engineering,the effect ofgroundwater on the stability of loess slope is obtained.（3） The distribution range of ancient landslides and buried surface depths of the original slope are explored,and the inherent relationship between the collapse of ancient landslides and loess slopes and the causes of collapse are found.（4） The height of this loess extra-high slope exceeds the applicable scope of the relevant regulations,but after a special argumentation and study,comprehensive measures such as vertical infiltration wells,anti-slide piles and retaining walls are adopted to ensure the stability of the slope.（5） This engineering provides reference for similar high soil slope management.