高聚物堆石料回弹特性试验

Tests on resilient behaviour of polymer rockfill materials

基于中型三轴仪开展了高聚物堆石料回弹模量试验,分析了高聚物堆石料卸载-再加载的力学特性和回弹模量变化规律。结果表明:围压和应力水平对体积变化规律有明显影响,随着试验围压的增大,试样由初始状态的剪胀逐渐变为剪缩;高围压下,随着应力水平的增大,试样的卸载体缩量呈非线性增大;而围压在100 kPa下,卸载时表现为体胀,不同应力水平下的卸载体缩量相近且较小。平均回弹模量与初始模量的比值大约在3.9～4.2之间,应力水平为0.7条件下对应的回弹模量与平均回弹模量较为接近。高聚物堆石料的回弹模量满足邓肯-张模型关系,数值计算过程中回弹模量系数近似为初始模量系数的4.0～4.2倍。

The resilient modulus tests of polymer rockfill materials were performed using a middle-scale triaxial instrument. Mechanical properties of polymer rockfill materials and their evolution laws of resilient modulus were analysed under unloading and reloading conditions. The results showed that the volume-contraction was influenced by the confining pressure and stress level significantly. The specimen gradually changed from the initial state of shear dilation to shear contraction with the increase of confining pressure. Under high confining pressure, the unloaded volume-contraction increased nonlinearly with the increase of the stress level. At the confining pressure of 100 kPa, the specimen presented a volume-dilation during unloading, and the values of unloaded volume-contraction were similar and smaller at different stress levels. The ratio of the average resilient modulus to initial Young＇s modulus was approximately between 3.9 and 4.2 under different confining pressures. The corresponding resilient modulus at the stress level of 0.7 was similar to the average resilient modulus. The Duncan-Chang model was applied to simulate the resilient modulus of the polymer rockfill materials, and the resilient modulus coefficient was approximately 4.0 to 4.2 times of the initial Young＇s modulus coefficient in the numerical calculation process.