Study on Sliding Characteristics and Controlling Measures of Colluvial Landslides in Qinghai-Tibet Plateau

摘要

Most landslides in Qinghai-Tibet Plateau take place in the Quaternary strata. Reasonable deformation mechanism, analyses method and controlling measures are proposed to treat colluvial landslides in this paper. Combined with the regional geological conditions of a colluvial landslide located at Road S101 Line of Qinghai Province, distinctive influencing factors were analyzed, including adverse physical and mechanical properties, geometrical structure, coupled fluid and thermal process. Slope stability was simulated by finite difference method. Displacement and shear strain in the lower part of sliding body are both higher than the upper part in saturated condition, consistent with the actual sliding characteristics. According to the geological comprehensive analyses and numerical simulation, the deformation mechanism, temporal and spatial evolutionary processes were summarized. The results show that freeze-thaw cyclic process of stagnant water during winter and spring make shallow deposits creep continuously and slide ultimately. Saturated condition caused by rainstorm in summer or autumn makes the slope slide integrally, and draws the mudstone at back to slide subsequently. The suitability and practical feedback of various kinds of controlling measures applied to colluvial landslides in cold regions were discussed. Micropile has significant elastic flexibility and unloading ability, and so can adapt to the mechanical change and sliding process of slope during freeze-thaw process. Both practical application and numerical calculation indicate that micropile is an appropriate choice against colluvial landslides in Qinghai-Tibet Plateau.