基于时序InSAR的覆砂石尾矿坝形变演化研究

为解决目前采用在尾矿坝坝体及滩面覆盖砂石进行防尘治理与闭库，但传统监测手段难以实现坝体整体监测的问题，采用时序InSAR技术对2014年10月至2018年7月的Sentinel-1A影像进行处理，提取了对应时间段内卡房尾矿坝的形变信息，并结合实地调查及尾矿坝建设资料，研究了卡房尾矿坝的时序形变演化规律。结果表明:SBAS InSAR监测到坝体出现第1次异常形变加速运动时间与坝体开始铺设砂石工程的施工时间节点完全吻合，体现SBAS InSAR技术在受人为工程影响的坝体形变监测方面具有极高的敏感性。坝体在施工结束后，坝体形变加剧趋势并未缓解，并且出现2次加速现象，分析认为是由于在坝体铺设约2 m厚的碎砂石极大地增加了坝体荷载，打破了坝体原有的应力平衡状态，且识别出雨季对坝体形变影响显著，表明铺设砂石会使得降雨在坝体中的停滞时间加长，进一步引发非雨季期间坝体形变加剧。研究结果不仅能还原坝体出现异常形变的时间与演化过程，而且还可以对引起异常形变的内在影响因素进行分析与论证，对指导尾矿坝灾害识别、分析与治理具有重要的指导意义。

Study on deformation evolution of sandstone covered tailings dam based on time series InSAR

A measure that repair and closure tailings pond by covering with sand gravel on tailings dam body and bach surface has been used,but it is difficult that traditional monitor methods to achiene overall monitoring.The Sentinel-1A images from October 2014 to July 2018 were processed by using the time series InSAR technology,and the deformation information of the Kafang tailings dam in the corresponding time period were extracted.Combined with the field investigation and construction documents of the tailings dam,the time series deformation evolution laws of Kafang tailings dam were studied.The results showed that through the monitoring of SBAS InSAR,the time of the first abnormal deformation accelerated movement appeared on the dam body was completely consistent with the construction time node of starting laying the sandstone engineering on the dam body,which proved that the SBAS InSAR technology had extremely high sensitivity in monitoring the dam body deformation affected by the human engineering.When the construction of dam body was finished,the aggravation trend of dam body deformation had not yet been alleviated,and the secondary acceleration phenomenon appeared.Through the analysis,it was concluded that the load of dam body increased greatly due to the laying of sandstone with the thickness of 2 m on the dam body,so the original stress balance status of the dam body was broken.It was also recognized that the rainy season had significant influence on the deformation of dam body,and the laying of sandstone would make the stagnation time of rainfall in the dam body lengthen,which further aggravated the deformation of dam body during the non rain season.The results can not only restore the time and evolution process of abnormal deformation on the dam body,but also analyze and demonstrate the intrinsic influence factors causing the abnormal deformation,which have important guiding significance for the recognition,analysis and treatment on the disasters of tailings dam.