Study On Stability Of Highway Accumulated Slope Under Earthquake And Reservoir Water

The deposit slope is widely distributed in our country,and it is easy to lose stability under the action of earthquake and reservoir water.Especially in Yunnan,the geological hazards of the deposit slope are especially serious.Based on Jinjidadan River Bridge,a controlling project of Dali-Yongsheng Expressway in Yunnan Province,this paper simulates the static and dynamic response of slope under different reservoir water levels and seismic intensity by two-stage method,limit equilibrium analysis and finite element method,and adopts safety factor and permanent displacement.The stability of slope is evaluated and the effect of reinforcement measures is discussed.The main research work is as follows:Analysis of topographic and geological structure and seismic load of reservoir water.Based on the historical data of Ludila Reservoir before and after impoundment,through field geological survey,exploration and UAV aerial survey,the main strata of the project site are identified,and a three-dimensional scene model is constructed.It is considered that there is no large-scale sliding phenomenon in the slope of the reservoir bank at present,but there is a long-term stability problem.The highest and lowest hydrology in the reservoir area are defined,and the peak acceleration of the site with seismic intensity of VI and VIII is given,which provides a geological generalized model and seismic load of reservoir water for the study of slope stability of accumulation body.Qualitative and quantitative evaluation of stability of typical sections based on two-stage method and limit equilibrium theory.Seven analysis profiles of slope on both sides of Shaoxing Island and highway were selected,and the overall stability of bank slope and the potential scope of bank collapse were analyzed by two-stage method.The multi-scheme working conditions of reservoir water fluctuation and seismic intensity were designed,and the stability of accumulative slope was quantitatively evaluated by limit equilibrium M-P method.The right-amplitude section along bridge position on both sides of the bank was prone to accumulations under the combination of reservoir water sudden drop and earthquake.Slope instability is regarded as the key research object of static and dynamic stability and effect analysis of reinforcement measures.Static and dynamic stability analysis of key sections based on stress-seepage coupling theory.The seep/W,quake/W,sigma/W and slope/W modules of Geostudio software are used synthetically to analyze the distribution characteristics of pore water pressure and strip safety coefficient under different working conditions are analyzed,and the evolution law of overall safety factor of slope with reservoir water variation is studied.The acceleration of typical monitoring points of slope is studied by equivalent linear analysis method.The lag effect and amplification effect of seismic wave propagation are revealed,and the dynamic stability of the accumulative slope under the combination of low,high water level and degree earthquake is analyzed.It is considered that there is a risk of instability in the right amplitude of the along-bridge position on both sides of the Shaoxiang Island and the highway,which needs to be strengthened.Analysis of the effect of reinforcement measures for accumulative slope combined with safety factor and permanent displacement.Aiming at the right section along the bridge site on both sides of the Taiwan Strait,the engineering design scheme of anti-slide pile with diameter of 1.8m is selected.The distribution characteristics of safety factor of strips on potential sliding surface of slope before and after reinforcement are compared and analyzed.The average safety factor and permanent displacement are used as dynamic stability evaluation indexes to evaluate the reinforcement effect of accumulative slope under the combined action of reservoir water and earthquake.The results show that anti-sliding pile is effective.The pile scheme can effectively improve the slope stability and meet the requirements of the code.