EPS颗粒混合轻质土反复荷载下变形和阻尼特性  

Deformation and damping characteristics of EPS beads-mixed lightweight soil under repeated load-unloading

作　　者：李晶[1] 缪林昌[1] 钟建驰[2] 冯兆祥[2] 

机构地区：[1]东南大学岩土工程研究所,南京210096 [2]江苏省长江大桥建设指挥部,江苏泰州225300

出　　处：《岩土力学》2010年第6期1769-1775,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.50478072)

摘　　要：通过反复荷载三轴剪切试验研究了EPS颗粒混合轻质土在反复荷载下的变形和阻尼特性,分析了不同围压、不同水泥掺入比及不同土质条件下轴向累积应变、回弹模量及阻尼比随轴向总应变的变化规律。结果表明:轴向累积应变与轴向总应变呈线性关系,与轴向总应变的比值较大,且在不同条件下基本不变;回弹模量随围压和水泥掺入比的增大而增大。在一定的围压和水泥掺入比下,当应变小于8%时,砂土EPS颗粒混合轻质土的回弹模量大于淤泥质土EPS颗粒混合轻质土的回弹模量;当应变大于8%时,情况相反。回弹模量与轴向总应变的关系曲线可用递减的幂函数来拟合;EPS颗粒混合轻质土的阻尼比随轴向总应变的增大而增大,随围压和水泥掺入比的增大而减小,砂土EPS颗粒混合轻质土的阻尼比小于淤泥质土EPS颗粒混合轻质土的阻尼比,但以上变化和差别都非常小,阻尼比基本保持为一常数。Through repeated load-unloading triaxial shear tests,characteristics of deformation and damping of EPS beads-mixed lightweight soil under repeated load-unloading were studied. Laws between axial accumulative strain and axial total strain,between modulus of resilience and axial total strain,and between damping ratio and axial total strain were analyzed under different confining pressures,different cement-dry soil ratios and different types of soils. Results show that the axial accumulative strain and the axial total strain is a linear relationship. The modulus of resilience increases as the confining pressure and the cement-dry soil ratio increase. Under a range of the confining pressures and the cement-dry soil ratios,the modulus of resilience of sand type lightweight soil is larger than that of silty clay type lightweight soil when the axial total strain is smaller than 8%. While it changes to the opposite side when the axial total strain is larger than 8%. Curves between the modulus of resilience and the axial total strain can be fitted by diminishing power functions. The damping ratio of the EPS beads-mixed lightweight soil increases as the axial total strain increases,and decreases as the confining pressure and the cement-dry soil ratio increase. The damping ratio of the sand type lightweight soil is smaller than that of the silty clay type lightweight soil,but differences of the damping ratio between the two types of lightweight soil are small and the damping ratio is an approximate constant.

关 键 词：EPS颗粒混合轻质土 反复荷载 轴向累积应变 回弹模量 阻尼比 

分 类 号：TU443[建筑科学—岩土工程]