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

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.