Effect Of Rubber Content And Particle Size On Liquefaction Properties Of Fine Sand

In the context of waste tires hprming the environment and weak natural sand reserves,some scholars propose to mix the rubber particles of waste tires with sand as a seismic isolation material,use rubber particles to improve the liquefaction resistance of sand,and increase the shock absorption performance of the cushion,combined with its economic and environmental benefits,the application of rubber sand is of great engineering practical significance.In this paper,the effects of rubber particle volume content and particle size on the dynamic properties of fine sand under cyclic shear stress are studied by hollow torsion shear test,and the main research contents and conclusions are as follows:(1)Through the cyclic torsion shear test under the increasing of fixed torsional shear amplitude and torsional shear amplitude,it is found that the rubber volume content has a greater impact on the pore pressure development,stress path,strain development,hysteresis curve,dynamic shear modulus and damping ratio of rubber sand,while the rubber particle size has less influence on the development of pore pressure and stress path,and under the same research content,the influence of rubber volume content is also greater than the influence of rubber particle size.(2)Through the cyclic torsional shear test under fixed torsional shear amplitude,the pore pressure development,stress path,and generalized shear strain development of rubber sand were studied,the influence of rubber particle volume content and particle size on the above characteristics was discussed,and the influence of stress and strain failure standards on the liquefaction resistance of rubber sand was analyzed.It was found that the overall law under the two destruction standards was consistent,the larger the volume content of rubber particles,the higher the liquefaction resistance of rubber sand,the larger the rubber particle size,the weaker the liquefaction resistance of rubber sand.(3)Through the cyclic torsional shear test under the gradual increase of torsional shear amplitude,the dynamic shear modulus and damping ratio of rubber sand were studied,the influence of different torsional shear amplitude,rubber particle volume content and particle size on the above characteristics was discussed,and the seismic isolation energy consumption of rubber sand was analyzed.It is found that with the increase of torsional shear amplitude,the dynamic shear modulus of rubber sand gradually attenuates,and the damping ratio gradually increases.The addition of rubber effectively alleviates the attenuation of the dynamic shear modulus of fine sand.Compared with the rubber particle size,the rubber content has a more obvious effect on alleviating the attenuation of dynamic shear modulus.(4)Through the cyclic torsion shear test under the increasing torsional shear amplitude and torsional shear amplitude,the hysteresis curve change of rubber sand was studied,the influence of torsional shear amplitude,rubber particle volume content and particle size on the above characteristics was discussed,and the elastic-plastic deformation conversion of rubber sand was analyzed.It was found that rubber sand had more plastic strain at small torsional shear amplitude,and began to show elastoplastic strain under a certain torsional shear amplitude,and the plastic strain continued to accumulate.With the increase of the volume content of rubber particles,rubber sand is gradually transformed into elastic deformation from elastoplastic deformation,and with the increase of rubber particle size,the rubber sand hysteresis loop will be significantly offset due to the movement of rubber sand in the sample.