A Novel Linear Relationship for Calculating Dynamic Shear Modulus of Geomaterials

The dynamic shear modulus G of soil was determined using a dynamic triaxial test system(DTTS) together with a fitting method.First,a novel linear relationship between G and damping ratio λ was proposed,which was used to select the appropriate G.Then,a hyperbolic model was constructed using the optimized parameters a and b representing the intercept and slope,respectively,from the linear regression of 1/G and dynamic shear strain γd.Finally,the differences between the tested and predicted results for G were analyzed for different soil types.The experimental results show that this linear relationship can overcome the shortcomings of the nonlinear relationship found in the large deformation stage and can predict λ in the hysteresis loop that is not closed case.In addition to Baoji loess,G was slightly larger(10%) than the experimental curve in the elasto-plastic stage;however,the experimental results show that the attenuation curve of G for Baoji loess is greater than the calculated value in the elasto-plastic stage.The test and analysis results will improve the knowledge of the dynamic properties of soils and also provide reliable values of G for further evaluation of seismic safety at engineering sites.