Experimental Study On The Dynamic Shear Modulus And Damping Ratio Of Gravel Soil

Gravelly soil is distributed in most areas of our country,especially in the area of Jiayuguan,Gansu,where the soil of experiment is taken from the area.For gravel soil have many research in terms of statics,but the research on dynamics is not perfect.Due to breccia is the large content of gravel soil,the size of the sample is larger than others and the shrinkage treatment is generally needed.Therefore,it is very important to study the effect of the size effect on the test results.In this paper,a series of experimental studies on gravel soils,which were carried out by using GCTS small and large dynamic triaxial tester.The effects of confining pressure,particle size distribution,specimen diameter on soil dynamic stress,dynamic shear modulus,damping ratio,maximum dynamic shear modulus,maximum damping ratio,and the test data were normalized.The experimental results show that with the increase of dynamic strain,the dynamic stress increases nonlinearly,the dynamic shear modulus is hyperbolic,the nonlinearity decreases,the damping increases nonlinearly,and the discretization decreases after normalization.With the increase of confining pressure,the stress corresponding to the same strain increases,the dynamic shear modulus increases and the damping ratio decreases.At the same time,the maximum dynamic shear modulus increases and the maximum damping ratio decreases.Finally,the dynamic shear modulus and damping were fitted with Origin,and the hyperbolic model relationship was modified.The effect of the scale effect on the shear modulus and damping ratio of the gravel soil is the same.The strain of the original strain is less than that of the crushed soil.The dynamic shear modulus of the original soil is less than that of the crushed soil The maximum damping ratio is less than that of crushed soil samples,the maximum damping ratio,the maximum damping ratio,the maximum damping ratio,the maximum damping ratio,And the experimental data are fitted to conform to the HD hyperbolic model.The effect of the diameter of the specimen on the shear modulus and damping ratio of the gravel soil increases with the increase of the diameter of the specimen,and the stress,dynamic shear modulus and maximum shear modulus of the same strain are increased,And the confining pressure 150 kPa,with the sample diameter increases the maximum dynamic shear modulus and 50 kPa compared to the increase in the amplitude decreases,which speculated that the sample there is an optimal diameter,when the sample diameter exceeds this value,The maximum dynamic shear modulus and the maximum damping ratio will not change with the increase of the diameter of the sample.At the same time,the maximum dynamic shear modulus measured by the large diameter sample is also closer to the empirical formula The size of the specimen has little effect on the damping ratio and the maximum damping ratio,and the regularity is not strong.The research results can provide reliable dynamic characteristic data for the seismic design of various geotechnical engineering,Which is more scientific and economical in engineering design.At the same time,enriched the dynamic characteristics of gravel soil research,for the relevant theory to provide reliable test data.