Evaluation of Potential Failure of Rock slope at the Left Abutment of Jinsha river Bridge along Lijiang-Xamgyi’nyilha railway, China

Abstract

Keeping slope relative stable has very significant meaning in traffic design and the safety of human life. Jinsha river Bridge is located on Tiger Leaping Gorge town along Lijiang-Xamgyi’nyilha railway, China. The left bank slope at bridge site, which composes of moderately thick layer of slate overlain by schistose basalt, is considered as potential instability due to two sets of joint planes. A comprehensive method based on geotechnical field and laboratory analyses, engineering model test and numerical analysis is adopted to assess slope stability under bridge foundation and seismic loads. According to model test, failure mainly initiated at the toe with shear movement along the joint planes, eventually resulting in the sliding along the slope surface and formation of tension crack at the crest of the model. This result coincides with computer-based modeling using Universal Distinct Element Code (UDEC), which shows that slope surface will produce loosening damage and slipping expected along the joint planes under different loading conditions. Moreover, the results of FEM analysis indicates that the rock mass under the main pier has potential shear failure region and it has developed along excavated slope. Through bridge site investigations, the bridge foundation should be strengthened to prevent the slope failure under external forces.