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  

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

作　　者：王庶懋[1] 高玉峰[1] AliH.Mahfouz 

机构地区：[1]河海大学岩土工程研究所,南京210098

出　　处：《防灾减灾工程学报》2007年第2期171-176,共6页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金资助项目(50479020)

摘　　要：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。There exists critical cyclic stress ratio Sth when lightweight sand-EPS beads soil （LSES） is subjected to cyclic loading. Sth is defined as the largest value of cyclic stress ratios corresponding to the flat δ-N curve 8 is degradation coefficient of secant elastic modulus and N is cyclic number）. Meanwhile Sth is 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 （Vε/ Vs） are found to be the main factors affecting the value of Sth. Generally, increasing CC, decreasing ac and Vε/Vs can improve the value of S,h. However, under confining pressure of 200 kPa, specimen dt143 exhibits some distinct behaviors due to restructuring.

关 键 词：循环荷载 临界循环应力比 砂土与EPS颗粒混合的轻质土 割线弹性模量衰减系数 

分 类 号：TU441.5[建筑科学—岩土工程]