Study On The Slope Stability Of Tianshang Grand Bridge In Yunnan Province

The Zhaoqiao secondary highway,which belongs to Yunnan Tianshang Bridge,is one of the main arterial traffic for poverty alleviation in southwest China.Geological disasters caused by various geological activities such as plate compression and neotectonics have seriously affected the operation and maintenance of this line.The foundation slope of Tianshang Bridge,different from other general slopes,is high-steeped rock slope,with the height of more than200 meters.The influence of various uncertain internal and external factors,such as engineering geology,slope lithology,rock mass structure,joint structural plane and meteorology and hydrology etc,makes the mechanism of deformation and damage of the bridge slope very complicated,and it is also very difficult to analyze its stability.Therefore,it is necessary to use a relatively complete set of comprehensive analysis means to study the slope stability of Tian Shang bridge foundation.This article mainly takes the foundation slope of Yunnan Tianshang bridge as the research object,on the specific theoretical basis of geological survey and rock mass mechanics,using the ARCGIS land spatial analysis based on ASTER-DEM numerical elevation model,the stability analysis of structural plane of rock mass,the natural and stable slope Angle analysis,the reasonable assessment of bridge foundation’s position and other technical means,from the easy to the difficult and complicated,step by step,the stability of bridge foundation slope is analyzed.Then,the three-dimensional numerical simulation model of the bridge foundation slope was established by using FLAC3 D software to quantitatively study the slope mechanics and damage characteristics under the respective or combination of various external factors such as self-weight state,bridge load,rainstorm effect,earthquake effect,etc.,and conduct in-depth simulation analysis on the stability of the bridge foundation slope.Through field investigation,theoretical discussion,formula calculation,numerical simulation and other methods,it can be concluded that the slope of bridge foundation of Tianshang Bridge conforms to the safety requirements of engineering;while the position of no.5 bridge foundation is unsatisfactory,thus backfill soil reinforcement or other protective reinforcement measures should be adopted in the actual project.The overall stability of the slope is fine,only local instability is likely to occur,it needs to be strengthened.This bridge foundation slope can meet the overall stability requirements under a certain earthquake,and can meet the engineering requirements.According to conventional slope stability analysis,based on the morphological characteristics and structural characteristics of slope body,it is also necessary to analyze slope body’s damage mode as well as establish a reasonable geological model,and research and evaluate the stability of the planned slope of Tianshang Bridge foundation adopted by scientific analysis method.The correct and reasonable evaluation can not only provide a reference for the protection of the existing bridge foundation slope,but also play a guiding role in the safety and reliable design of the bridge site in the future,saving economic investment for the construction of the bridge and avoiding huge economic losses.Strengthening the study on the stability of high and steep slopes in such complex rock mass has extensive technical,economic and social benefits for highway construction,prevention and control of geological disasters and protection of geological environment in alpine canyon region in southwest China.