西气东输管道工程陕西岭湾村滑坡变形特征及成因机制分析

Analysis on deformation mechanism of the Lingwan Village landslide in Shaanxi Province section of the West-East Gas Pipeline Project

以西气东输管道余家坪镇岭湾村一处正在变形的黄土滑坡为研究对象,基于现场勘察、InSAR、GNSS监测和深部位移监测等,分析滑坡2017—2022年的变形特征及滑坡成因机制。研究表明:滑坡地下水位已达坡脚,滑坡前缘形成多处“土溜”,滑坡地表垂直潜蚀裂缝发育,后缘可见贯通的裂缝,滑坡内管道周边裂缝发育;InSAR数据显示滑坡一直缓慢变形,年变形量2.0~4.0 cm;GNSS变形及裂缝变形显示,2020年8月至今地表变形速率增大,变形明显,变形量在4~10 cm;深部变形监测数据变化量在0.05~1.36 mm,变化很小;降雨及土体含水率数据分析表明滑坡在暴雨后发生位移变形。综合分析监测数据表明,岭湾村滑坡属于降雨诱发的浅层滑坡;区域内的自然强降雨、人类工程经济活动作为滑坡的诱发因素,对滑坡的发生及发展作用明显。结合管道应变监测数据,目前西气东输管道遭受滑坡灾害的风险可控。

Based on field investigation,InSAR,GNSS monitoring,and deep displacement monitoring,a deformed loess landslide in Lingwan Village,Yujiaping Town,West-East Gas Pipeline Project was analyzed to understand its deformation characteristics and landslide formation mechanism from 2017 to 2022.The analysis shows that the groundwater level of the landslide has reached the toe of the slope,and numerous soil slips have been formed at the front edge of the landslide.The surface of the landslide exhibits vertical subsurface erosion cracks,while the penetrating cracks can be seen at the trailing edge.InSAR data shows that the landslide has been slowly deformed,with an annual deformation rate between 2.0-4.0 cm.GNSS deformation and crack deformation show that since August 2020,the surface deformation rate has increased significantly,with a deformation rate between 4.0-10.0 cm.The variation of deep deformation monitoring data is minimal,between 0.05 to 1.36 mm.Analysis of rainfall and soil moisture data shows that the landslide has displacement deformation after rainstorm.The comprehensive analysis of monitoring data reveals that the landslide in Lingwan Village is a shallow landslide induced by rainfall.Natural heavy rainfall and human engineering economic activities in the region are the primary inducing factors for the occurrence and development of landslide.Combined with pipeline strain monitoring data,the risk of landslide disasters in Shaanxi Province section of West-East Gas Pipeline Project is controllable.