Expanded poly-styrene(EPS) is a new material to reduce the subsidence of the bridgehead of soft embankment.Traditional design and material selection of EPS embankment does not take into account the basic characteristics of creep. Creep tests of EPS specimens in varied density and pressure are performed. Results are as follows: Uniaxial compressive strength and anti-deformation ability of EPS linearly rise up with increasing density; creep deformation of EPS depends on the stress factor.Creep deformation increases closely linearly with the stress factor and becomes stable fast when the factor is less than 0. 6.However the creep deformation increases nonlinearly and rapidly and becomes unstable when the factor is more than 0.6.Conclusion from the creep test can determine the design value of compressive strength of EPS and the corresponding density requirements. The relation between the creep deformation and time follows the hyperbolic curve, and the corresponding constitutive creep relation is presented. The method to obtain the parameters is introduced. Case studies show that the constitutive relation of EPS presented better reflects the creep behaviors of EPS.%泡沫聚苯乙烯(EPS)是一种有效防治软土地基桥头跳车的超轻质填料,以往EPS路堤设计及材料选用方法中基本没有考虑材料蠕变特性的影响.笔者对不同密度、不同压力下的EPS试样进行了一系列压缩蠕变试验.结果表明,EPS的蠕变变形值依赖于应力水平因子,当应力水平因子小于0.6时,蠕变变形与应力水平因子近似呈线性关系且很快稳定,当应力水平因子大于0.6后,蠕变变形呈非线性快速增长且难以稳定,根据蠕变试验结论可以确定EPS抗压强度设计值和相应的密度要求;蠕变变形与时间之间符合双曲线关系,据此建立了压缩蠕变本构方程,并给出了方程中参数的确定方法.试验数据分析表明,建立的EPS蠕变方程能较好地反映EPS的蠕变特性.
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