Study Of Dynamic Characteristic Test Of Clay-Sand Layered Composite Sample

Natural stratum is distributed mostly in stratification. In real projects,the dynamical character of the particular ground is needed to be identified,therefore experimentations about the characters of different earth layers have to be identified through related sampling separately. According to the results from those experimentations,other parameters on the dynamical characters are reckoned with variation theory or lumped mass method,and even the applicable parameter on the dynamical characters of natural stratum is needed to be calculated through finite element method in complicated situations.Besides,the destined site should be treated with Changing and Filling,thus the dynamical characters of the earth refilled should be identified in order to make the quantum of the refilling economical and secure.With such background and in line with the current research topic-study on the dynamical interaction between building's superstructure and foundation by the construction department of Hunan province,this dissertation dedicates to hold dynamic triaxial experimentations separately on three kinds of indoor preparation clay-sand layered composite sample,the sample of sand and the sample of clay in conditions of indifferent confining pressure (σ₃=100kPa,σ₃=200kPa,σ₃=300kPa) and indifferent consolidation ratios( K_c=1.0 and K_c=1.5) ,thus the law on the dynamical characters of the three samples being gained and their differences being recognized significantantly through comparative analysis of the experimentation results.Proved by the experimentation results,sand-clay layered composite sample is similar to the sample of clay in such dynamical characters as the character of hysteresis loop,the configuration of the hysteresis loops,dynamic modulus and damping ratio,indicating that sand and clay have different degrees of contribution to the dynamical characters of sand-clay layered composite sample,with the sample of clay having larger degree of influences.Actually,in stratified site,clay layer has a larger degree of influence on the parameter of the dynamical characters of the whole groundsill than the sand layer.The experiment results are expected to provide practical guidance for the seismic work in the treatment of the site in real projects and validating data for further theoretical analysis as well.