Analysis on dynamic properties of crushable coarse-grained soil under undrained conditions
Under seismic loads,coarse-grained soil materials like rockfill materials usually crush,which leads to their dynamic features are distinct greatly from those without particle breakage.In order to investigate the cyclically dynamic properties of crushable grain materials,dynamic triaxial tests are performed on these kinds of materials under consolidation undrained(CU)conditions with the frequency of 1.0 Hz,and the applied confining pressure is respectively 100,200,300 and 400 kPa.It is experimentally demonstrated that all the samples were axially contracted at failure,and behave strain hardening.The axial strain curves can be divided into three stages of the initially rapid increase stage,the middle stability stage,and the last failure stage,and the duration for the three stages is distinct,so is the variation of the samples.With the increase of the cyclic times,the dynamic pore pressure will increase,and the higher the excitation force under the same confining pressure,the faster the dynamic pore pressure rises.For the dynamic strength,the smaller the stress ratio,the lower the dynamic strength curve.The damping ratio increases in a whole with the increase of dynamic shear strain,and under the same confining pressure,the smaller the axially excited force,the smaller the damping ratio.Many factors including the excited force,confining pressure,the cyclic number can affect the particle crushing,and their contributions to particle breakage vary greatly under the same confining pressure(or the axially excited force),and with the increasing confining pressure,the grain crushing occurs more easily.
NETL
NSTL
万方数据
维普
