Study on dynamic modulus and damping ratio of sand gravel under different loading ratios

In order to explore the dynamic characteristics of sand gravel under the action of loading ratio, through large-scale dynamic triaxial tests, the change laws of dynamic modulus and damping ratio of sand gravel under different loading ratios and confining pressures is studied, and the influence of different loading ratios and confining pressures on the dynamic parameters of sand gravel was analyzed. The results show that: (1) With the increase of loading ratio, the dynamic strain increases significantly, the pore pressure increases significantly, and the maximum damping ratio increases; (2) The test data can better reflect the variation law of damping ratio with the development of dynamic shear strain. Considering the changes of various dynamic parameters, it is suggested that the selection range of loading ratio of dynamic modulus and damping ratio test of gravel should be 1.5-2.0; (3) The test data with dynamic strain less than 0.01% and dynamic strain greater than 0.01% are fitted by the subsection fitting method. The fitting degree between the straight line and the test point is greater than 0.96, and the subsection fitting is more reasonable under different test conditions; (4) Under different test conditions, the dynamic shear modulus ratio and the reference shear strain have good normalization, and the test data are reliable. Through binary linear regression, the empirical formula of the maximum dynamic shear modulus of gravel about confining pressure and loading ratio is obtained. This method can provide a reference for dynamic triaxial test and data processing of gravel materials.