Study On Dynamic Instability Mechanism For The Riverside Subgrade Under The Effect Of Dynamic Factors In Mountainous Area

Because of the dynamic change of reservoir water,the reservoir bank roadbed is different from common highway roadbed,and the design,protection and instability mechanism of the reservoir bank are special.The changing of water level,water yield and velocity of water make the hydrodynamic conditions of the subgrade edge change.Under stress field and seepage field,the internal structure of the subgrade changes,resulting in roadbed instability,which is a dynamic process.A lot of scholars did a lot of research on the effect of reservoir water on the roadbed,but these studies tended to focus on unilateral effect without forming the system,which included mechanism,protection and application,and it was not considered that the subgrade should be protected from the angle of the reservoir operation.Therefore,in order to solve the key technical problems in mountain reservoir bank subgrade protection project and provide a basis for the establishment of a scientific and effective bank roadbed protection design methods,it is necessary for in-depth study of reservoir water influence on the subgrade based on roadbed dynamic instability mechanism,and scientific protective measures should be put forward.Therefore,based on summarizing a lot of research results and using the method of numerical simulation and theoretical analysis,dynamic instability mechanism for the riverside subgrade and operating parameters of Zhou-Ba power station reservoir and roadbed protection reinforcement measures for S103 lines were studied.The following aspects of the research work was carried out:(1)The types,instability factors and failure modes of reservoir bank roadbed were expounded in detail,which provided a basis for the scientific resolution of the state of the roadbed;(2)The basic mechanism of fluid solid coupling,the seepage characteristics of reservoir bank roadbed and the principle of fluid structure interaction in the failure process of reservoir bank roadbed were expounded.By studying the interaction mechanism between seepage field and stress field,the mathematical model of fluid structure interaction was introduced;(3)Using FLAC3D analysis software and flow solid coupling theory,numerical analysis model and numerical analysis of the Sichuan Provincial Highway S103 line bank roadbed was established.The influence of factors that included static water and reservoir water level rising and falling rate on the bank roadbed was studied.It is found that the reservoir water level fluctuation rate had a great influence on subgrade stability,and with the increase of water level elevating rate,embankment safety coefficient gradually declined.(4)Based on the analysis of fluid solid coupling theory and numerical simulation,the reasonable rate of rising and falling of the reservoir water level is obtained;(5)According to the actual situation of Sichuan Provincial Highway S103 line,by numerical simulation analysis,protective measures and the various protection measures of suitability evaluation were proposed.The research is significant to solve the problem of Sichuan provincial S103 line,and the theoretical basis is provided to determine the operating parameters of Zhou-Ba power station.At the same time,to solve the problem of similar mountainous reservoir bank subgrade protection reinforcement,a foundation is laid.