Analysis of dynamic properties of loess in Weibei area under cyclic loading
In order to study the dynamic characteristics of loess in Weibei area,the dynamic constitutive relationship and dynamic backbone curve of loess under different confining pressures were studied by TYS-20 soil dynamic triaxial testing machine.The relationship between dynamic shear modulus ratio and damping ratio of loess was analyzed,and a dynamic shear modulus attenuation model and a damping growth model were proposed.The influence of different confining pressures on the dynamic strength and residual strain of loess was studied,and the reasons for the change of dynamic characteristics of loess were explained theoretically,so as to better ensure the minimization of the influence of loess seismic subsidence on underground space.Finally,the microstructure of loess before and after earthquake was compared,and the mechanism analysis was carried out to provide theoretical significance for the development of underground space in this area.The results show that the dynamic constitutive relationship of loess conforms to the hyperbolic model,and the dynamic shear modulus ratio decreases exponentially with the dynamic shear strain,while the damping ratio increases logarithmically with the dynamic shear strain.The dynamic strength and dynamic strength index are greatly affected by the test conditions,and the dynamic strength increases with the increase of confining pressure,indicating that the dynamic strength analysis can better explain the dynamic characteristics of loess.The microstructure of soil before and after earthquake is compared by electron microscope.The microstructure of soil before and after earthquake is compared by electron microscope,and the mechanism analysis is carried out,which provides theoretical support for the development of underground space in this area.The results show that the loess in Weibei area,which belongs to slight seismic subsidence area,is less prone to vibration deformation under cyclic loading.
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维普
