| In order to reveal the dynamic characteristics of Loess under complex consolidation stress,in this paper,the dynamic Shear stress-strain relation,the dynamic strength and the relation between the seismic subsidence deformation and the principal stress Coefficient b,the water content and the confining pressure of the consolidation of loess under true triaxial consolidation are studied by using the dynamic torsional shear apparatus,the relationship between the seismic subsidence Coefficient of Undisturbed Loess and the vibration times,water content,confining pressure and principal stress Coefficient b during consolidation is also analyzed and discussed:(1)Under Cyclic torsional shear loading,the dynamic shear strain of Loess develops gradually,which ranges from 10-5 to 10-2.The Dynamic Shear stress ratio tends to be consistent with the dynamic shear strain curve under the condition of different intermediate principal stress Coefficient b consolidation.(2)In the course of shear failure of Loess,the shear strain develops gradually and the dynamic modulus decreases.The Comprehensive Physical Index is introduced to compare with the previous research results,and the constitutive index of Loess is calculated by Physical Index,the relationship between the maximum dynamic shear modulus and the consolidation stress and the structure degree is analyzed.(3)The variation of damping ratio of Loess with the Principal Stress Coefficient B,water content and confining pressure during consolidation is compared and analyzed in the tests of dynamic characteristics of Loess under progressive loading.When B value varies from 1 to 0.25,the friction between soil particles increases the damping ratio.The damping ratio of Loess under different influence factors is analyzed and the curve fitting formula between damping ratio and dynamic shear strain of Loess is established.(4)The dynamic strength of Loess is different under different b value,humidity and consolidation stress.The dynamic strength index of Loess under different moisture content is analyzed.(5)When water content and consolidation confining pressure are constant,the axial accumulative deformation of Loess increases with the decrease of Principal Stress Coefficient b.When the water content and b value are constant,the seismic subsidence deformation is relatively small under high confining pressure consolidation.At the same confining pressure and b value,the seismic subsidence increases significantly under the condition of high water content.The relationship between the Coefficient of seismic subsidence and the Times of vibration is analyzed.It is found that the axial accumulative deformation rate of Loess is larger at low times than at high times.(6)The relationship between seismic subsidence Coefficient and dynamic shear strain of Loess under different influence factors is fitted,and the empirical formulas between Seismic Subsidence Coefficient and b value,water content,consolidation confining pressure and vibration times are established. |
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