砂土与EPS颗粒混合的轻质土(LSES)临界循环应力比的试验研究

循环荷载下,砂土与EPS颗粒混合的轻质土(LSES)存在临界循环应力比Sth,将割线弹性模量衰减系数δ与循环次数的关系曲线能保持平缓的最大循环应力比定义为Sth,它是结构稳定与破坏两种状态的界限指标,根据动三轴试验结果,认为影响Sth的主要因素有围压、水泥掺量和EPS颗粒含量。一般来说,水泥掺量的增加、围压和EPS颗粒含量的减小均会提高Sth,但由于高围压下的结构重塑,水泥掺量低且EPS颗粒含量高的试样的Sth表现出一些不同的性状。

Experimental Study on the Critical Cyclic Stress Ratio of Lightweight Sand-EPS Beads Soil(LSES)

There exists critical cyclic stress ratio Sthwhen lightweight sand-EPS beads soil(LSES) is subjected to cyclic loading.Sthis defined as the largest value of cyclic stress ratios corresponding to the flat δ～N curve δ is degradation coefficient of secant elastic modulus and N is cyclic number).Meanwhile Sthis considered as the threshold index differentiating two structural states,i.e.stabilization and failure.Based on the cyclic triaxial test data,confining pressure(σc),cement content(CC) and EPS beads content(Ve/Vs) are found to be the main factors affecting the value of Sth.Generally,increasing CC,decreasing σcand Ve/Vs can improve the value of Sth.However,under confining pressure of 200 kPa,specimen dt143 exhibits some distinct behaviors due to restructuring.