Study On Stability And Dynamic Response Of Slope With Weak Interlayer Under Pulse Seismic Wave

The stability analysis of slope is always a hot topic in geotechnical engineering field.In the current study of slope stability,homogeneous slope is the object of much research.China is a vast country with many mountains.There are inevitably many heterogeneous mountains in nature.Slope with weak interlayer,as one of representative;its stability has been widely concerned.As the discontinuous surface of strength in slope,the failure of slope instability often starts from interlayer,so the weak interlayer in slope becomes the controlling factor of slope instability.Earthquakes play an important role in the occurrence of landslides.China is located between two active seismic zone,higher frequency of the earthquake,the western mountains overlape with two seismic area,the earthquake can transform a fragile geological conditions become more severe.A large number of seismic disasters show that the occurrence of landslide is closely related to the near fault ground vibration,and the probability of the near fault area landslide is much higher than that of the far earthquake area.The finite difference program FLAC3 D is used in this paper to analyze the slope model.The static safety factor of homogeneous soil slope,rock slope,soft interbedded slope and dynamic safety factor under pulse velocity wave are discussed by using various criteria to distinguish slope instability and the dynamic response and failure modes of soft interbedded slope under pulse ground vibration are discussed.The main work and research results are as follows:(1)Homogeneous soil slopes under four kinds of standards of the slope unstability of consistent safety coefficient,the safety factor of rock slope under the instability of 4 kinds of standards of safety factor though not consistency,but the difference is smaller.The results of FLAC3 D in calculating the slope safety factor of homogeneous slope are similar to those of the limit equilibrium method.(2)The existence of weak interlayer in slope will reduce the static safety factor of slope;The position of the weak interlayer on the slope has a great influence on the static safety coefficient of the slope,which shows that the lower the position of the interlayer in the slope,the smaller the static safety coefficient of the slope;Weak interlayer position less than half the high slope,soft interlayer position changes greatly influenced by the static safety factor of slope,soft interlayer position less than half the high slope,the location of the soft interlayer,will significantly improve the safety factor of slope;When the position of weak interlayer is more than one half,the slope static safety coefficient increases slowly with the increase of weak interlayer position,and the safety coefficient gradually approaches the homogeneous slope.The traditional limit equilibrium method is used to calculate the static safety coefficient of slope with weak interlayer.(3)Using the finite differential program FLAC3 D to simulate a single side slope of a vibrating table.By comparing the numerical simulation with the experimental acceleration amplification coefficient,it is found that the FLAC3 D simulation of single slope has a good effect,which has similar laws in the simulation of double slope.(4)It is found that the position and inclination Angle of the weak layer,slope height and slope Angle of soft interbedded slope will affect the dynamic safety coefficient of slope;The lower the location of the weak layer,the lower ability of the slope with weak layer can bear an earthquake and the the dynamic safety factor of slope will be lower.The dynamic safety factor of slope decreases with the increase of slope height and slope Angle.The failure mode of slope is obviously affected by interlayer.When the position of weak interlayer is less than half of slope height,slope failure occurs at interlayer.When the position of weak interlayer is higher than half of slope height,the shear outlet of slope failure is located at the foot of slope.The lower the position of the weak interlayer,the deeper the tensile failure will occur at the top of the slope.The higher the slope height,the greater the slope Angle,the deeper the tensile failure will develop at the top of the slope.(5)In order to research the dynamic response of slope with weak interlayer,the material parameters of slope under the condition of no reduction will bear three seismic wave input,by extracting key acceleration curve slope and slope,solving the corresponding acceleration amplification factor.By comparing the acceleration amplification coefficient of the interlayer at different slope positions,it is found that the acceleration amplification coefficient is generally enlarged along the height.The change of inclination Angle of weak interlayer has little influence on the acceleration amplification coefficient.The increase of the position of the weak interlayer will affect the acceleration amplification coefficient.The higher the position of the weak interlayer,the smaller the acceleration amplification coefficient,the closer the dynamic characteristics of the slope will be to the homogeneous slope.When the weak interlayer position is less than half the high slope,the double pulse seismic acceleration amplification factor is greater than the single pulse wave,when the weak interlayer position higher than half the high slope,single pulse under the action of seismic acceleration amplification factor is bigger than double pulse acceleration amplification coefficient of seismic wave.The change of slope height and slope angle significantly affects the law of slope acceleration amplification coefficient,the higher the slope angle,the greater the acceleration amplification factor.As the height and angle of slope increases,the acceleration amplification factor of slope will also insrease.The Angle of the weak layer affects the acceleration of the slope,the acceleration amplification coefficient of the slope with reverse weak interlayer is largest.