Evaluation On Engineering Treatment Methods Of Gaijiayin Mountain Landslide Of Lanyu Railway

Lanzhou-Chongqing Railway is one of key construction projects of the western development strategy. The line acrosses the slope toe of Gaijiayin Mountain Landslide directly and Weiyuan railway station is in the range of landslide influence, therefore, stability of the landslide directly affect the safety of railway construction and its operation in the future. Evaluating the effectiveness of engineering treatment methods which all designed by China Railway First Survey and Design Institute, to ensure the stability of the slope after transformation, has very important theoretical practical significance and realistic significance.Based on related geological data and combined with field investigation, this paper analyzed the engineering geological condition of Gaijiayin Mountain Landslide and found out characteristics of the boundary, the internal structure and the deformation of slipmass. Through the comprehensive geophysical prospecting test (including Rayleigh wave method and high density method), this paper made a more in-depth analysis of the internal structure characteristics, and explained abnormal area of the test results, inverted the sliding process of the landslide. Combined with the design data provided by China Railway First Survey and Design Institute, the safety factor of the landslide before and after treatment has been calculated by strength reduction method. Through numerical simulation by FLAC3D, the distribution characteristics of stress and displacement of the whole landslide before treatment have been discussed. Based on the engineering geological conditions and the results of numerical simulation, the paper focused on some problems that exist in engineering methods, such as anti-slide pile, drainage system and cutting work, and put forward some corresponding engineering suggestions.Through field survey, the analysis of geophysical prospecting test results and numerical simulation, we can draw the following conclusions and recommendations:(1) The present form of Gaijiayin Mountain Landslide was finished in two slip periods, there is no signs of sliding deformation at the back of the landslide because its strata has good lateral continuity.(2) Cutting work will decrease the local stability of slope, so the cutting area should be supported by rockbolt and shotcrete.(3)It’s very necessary to set drainage engineering outside the trailing edge of landslide and on the edge slope toe after leveling and lightening, the construction should guarantee its quality.