Study on dynamic characteristics of loess in Xi'an near-fault zone
In order to study the characteristics of dynamic shear modulus and damping ratio of loess in the near-fault area,the dynamic triaxial test was carried out by GDS dynamic triaxial tester with the loess in the near-fault area as the research object,and the dynamic shear modulus and damping ratio of loess were analyzed under the influence of confining pressure,saturation and frequency.The results show that the dynamic shear modulus of loess in the near-fault area is negatively correlated with saturation and consolidation ratio,and the decline decreases gradually,but it is positively correlated with the vibration frequency,and the amplification gradually decreases with the increase of vibration frequency.The dynamic shear modulus of saturated loess in the near-fault zone rebounds,and its value is higher than that of unsaturated loess,which may be due to the fact that the secondary fissures of loess in the fault zone are more developed.The dissolution of soluble salts in the soil skeleton by pore water increases,causing the soil to soften and enhance its viscosity,resulting in an increase in the required dynamic shear stress The damping ratio of loess in the near-fault zone is negatively correlated with saturation,confining pressure and consolidation ratio,and the decrease gradually decreases and finally tends to be stable.Saturation has the greatest influence on the damping ratio of loess,while confining pressure and consolidation ratio have little influence on the damping ratio.The damping ratio of undisturbed loess and remolded loess in the near-fault zone is roughly similar,indicating that soil disturbance has a relatively small impact on the loess at the Lishan Mountain front fault site.In this paper,the linear function in semi logarithmic coordinate system is used to quantify the relationship between dynamic shear modulus,damping ratio and dynamic strain,and the fitting effect is good.The results of this study can provide a reference for the analysis of the dynamic response mechanism in the near-fault zone.
active faultdynamic triaxial testloessdynamic shear modulusdamping ratio
万方数据
维普
