Research on the spatiotemporal evolution of deformation and seismic dynamic response characteristics of high-steep loess slope on the northeast edge of the Qinghai-Tibet Plateau

Abstract

The high-steep loess slopes located in the transition zone between the landforms of the Qinghai Tibet Plateau and the Loess Plateau are prone to instability under rainfall and earthquakes conditions. Analyzing their stability and potential instability areas can help solve the problem of disaster prevention and control of high-steep loess slopes under complex landforms. This article took the high-steep loess slope on the northeast edge of the Qinghai Tibet Plateau as the research object, used small baseline subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) to analyze the spatiotemporal evolution of slope deformation, and then used numerical simulation to research the static and dynamic response characteristics of slope. The results show that the slope deforms rapidly after heavy rainfall in August 2020, and the annual deformation rate is -11.2 ~ 3.0 mm/a within 5 years. The slope angle and slope height have an amplification effect on the peak ground acceleration (PGA) of slopes. PGA increases with the increase of slope height and slope angle, and the amplification coefficient of PGA reaches 1.67–3.18 times. Under natural, rainfall, and earthquake conditions, the displacement extremum zone of loess slopes is located at the shoulder of the slope. Based on the deformation spatiotemporal evolution characteristics and seismic dynamic response characteristics of loess slope, this paper identified three potential instability areas and instability factors of loess slope, providing theoretical support for the research of deformation and instability mechanisms of high-steep loess slopes on the northeast edge of the Qinghai Tibet Plateau.