EPS块体动变形特性的室内试验研究

Laboratory test study on dynamic deformation characteristics of EPS block

通过室内动三轴试验,研究了EPS(expanded polystyrene)块体在不同围压以及应力水平下的动力特性。试验显示,在不同围压下EPS的动应力-应变关系有很大区别,围压较低且当动剪应力比s<0.5时,dσ与dε呈线性关系,围压稍大时则为双曲线型。EPS的动应变dε和割线动剪切模量Gsec的特点与土也有很大不同,在加载的第一周dε即增长到较大值,此后,随循环次数N缓慢增长,直至稳定;Gsec则是先下降,而后缓慢增加,直至稳定。分析试验结果认为40kPa是EPS最合适的使用围压。

Based on laboratory dynamic triaxial tests, the dynamic properties of EPS （expanded polystyrene） block under various confining pressures and stress levels are studied. Tests show the dynamic stress-strain relationship of EPS is much different from that of soil. Under low confining pressure and s〈0.5, σd、εd relation is linear while it changes to hyperbolic-type under higher confining pressure. The characteristics of εd and secant dynamic shear modulus Gsec of EPS are also distinct. In the first load cycle, εd reaches a high value, and increases slowly to be almost constant. As to Gsec, it initially decreases, then increases to be stable. According to test results, 40 kPa is suggested as the optimal confining pressure in application.