Large-scale Triaxial Dynamic Test And Slope Dynamic Response Analysis Of Gobi Gravel Soil

In the reconstruction and expansion project of Xinjiang Urumqi International Airport,due to the large difference in topography between the north and south of the construction site,a large amount of filling is required for the new airport runway,and the filling materials are mainly Gobi gravel soil.The filling height of earth and stone is relatively large.According to the airport construction plan,the length of the slope with filling height exceeding 20 m is about 3000 m,and the slope is as high as about30 m.In order to guide the construction of Xinjiang Urumqi International Airport,reveal the dynamic characteristics of the Gobi gravel soil filling,and to understand the force and deformation characteristics of the high slope of the Gobi gravel soil fill under dynamic load,this paper developed the Gobi gravel soil filling large triaxial Experimental research on dynamic characteristics and numerical simulation analysis of slope dynamic response.The main research content and results of the thesis are as follows:(1)Based on the large-scale dynamic triaxial instrument to carry out the experimental research on the dynamic characteristics of the Gobi gravel soil,the dynamic stress and dynamic strain time history curves of the Gobi gravel soil were analyzed,and the dynamic stress and dynamic strain timehistory curves of the Gobi gravel soil were analyzed under different confining pressures,dynamic stress amplitudes,load frequencies and vibration cycles.A comparative analysis of the dynamic stress-dynamic strain hysteretic curve of the Gobi gravel soil reveals the basic characteristics of the dynamic stress and dynamic strain of the Gobi gravel soil.(2)Based on the results of the dynamic triaxial test,the dynamic constitutive relationship of the Gobi gravel soil was analyzed,and the relationship between the dynamic elastic modulus of the Gobi gravel soil and the dynamic strain amplitude and vibration frequency was discussed.Based on the Hardin-Drnevich equivalent viscoelastic model,the maximum dynamic elastic modulus and dynamic constitutive model parameters of the Gobi gravel soil under different test conditions were calculated,and the effects of confining pressure and frequency on the maximum dynamic elastic modulus were analyzed.(3)The normalized curve and curve fitting parameters of the dynamic elastic modulus ratio and dynamic strain amplitude of the Gobi gravel soil were obtained.The dynamic elastic modulus attenuation model of Gobi gravel soil was established,and the degradation formula and fitting parameters were given.The relationship between the damping ratio of the Gobi gravel soil and the dynamic strain amplitude was studied,and the maximum damping ratio of the Gobi gravel soil under different test conditions was given.(4)With the aid of the finite element analysis software PLAXIS 3D and the dynamic parameters of the Gobi gravel soil obtained from the experiment,a dynamic load model of the slope was established,which revealed the stress and strain changes of the Gobi gravel soil slope under the moving load of the aircraft,and discussed the Gobi gravel Dynamic stability of high soil slopes.