Study on Numerical Simulation of Slope Seismic Stability

Author:Zhang Zhaopeng

Supervisor:Bao Jingshan


Degree Year:2018





The results of a large number of earthquake damage investigations show that the vibration is difficult to directly kill a person.The real reason of casualties caused by earthquakes is the destruction of engineering structures caused by ground motion and secondary disasters.Slope instability is one of the most common secondary disasters,In mountainous or hilly areas,its damage sometimes even exceeds the damage caused by ground motion.Therefore,the research on slope stability has always been one of the key areas in geotechnical engineering and seismic engineering.Special geo-environment,active geological structure and rapid development of urbanization have made the stability of slopes particularly prominent in China.Therefore,in order to carry out risk assessment of slope hazard,seismic design and reduce losses caused by landslides,it is very important to actively carry out research work on seismic stability of slopes.In this paper,the numerical simulation method is mainly used to study the stability under the action of the slope,the research findings are as follows:1.The Geostuido software is used to calculate the seismic stability of slopeThe basic principles of the evaluation indexes of factor of safety and permanent displacement,and their respective more common calculation methods,are briefly introduced,and the Geostudio software is exploited to calculate the stability of slope.The process of slope stability study by Geostudio software is introduced in detail and compared the results of different evaluation indicators.2.The influence of slope shape on seismic stability of slopesThe field investigations indicate that the shape of the slope includes linear shape,convex shape,concave shape and polyline shape,through establishing corresponding numerical models,the influence of slope shape on seismic stability of slope is discussed.The results show that,firstly,the dynamic response distribution of different slope shapes is different,in general,there will be a magnification effect on the top and free surface for the input ground motion.Secondly,under the same strength of earthquake,the sequence of slope stability of different slope shapes from high to low is Internal folding shape,concave shape,linear shape,convex shape and outside folding shape.3.The influence of input ground motion on slope stabilityThe influences of amplitude,spectral characteristics and vertical ground motion input methods on the stability of the slope,the position of the most dangerous sliding surface and the dynamic response are studied.The results show that,firstly,the effect of spectrum characteristics on the location of the most dangerous sliding surface is superior to the amplitude and vertical ground motion input.Secondly,the dynamic stability of the slope decreases with the increase of the amplitude of the input ground motion and increases with the increase of the frequency of the input ground motion.Finally,different vertical ground motion input methods also have significant differences in the impact on slope stability.4.Simulating the sliding surface under the action of ground motionThrough the change of the plastic zone and generalized shear strain,FLAC3 D software is used to simulate the asymptotic formation process of the sliding surface forming under the action of the ground motion.At the same time,based on the results of the analysis,the effect of the load type,the damping form and boundary range on the position of the sliding surface are compared.5.The influence of determination methods of sliding surface on slope stability evaluationThe influence of different sliding surface determination methods on slope stability is studied.Through field investigations,Basic data of shenjiazui landslide which was caused by 8.5 magnitude earthquake of Haiyuan in 1920 are obtained,and taking this seismic landslide as an example,the influence of tension—shear sliding surface and shear sliding surface on the dynamic stability evaluation of slopes is compared.