考虑多因素的浇筑式沥青混凝土动力特性研究

浇筑式沥青混凝土心墙坝因在严寒条件下可施工和变形协调能力良好等优点,在新疆得到广泛应用。新疆是地震高发区,因此迫切需要对浇筑式沥青混凝土心墙坝的抗震性能进行研究。针对新疆某典型浇筑式沥青混凝土心墙坝工程,以该坝的心墙防渗材料为研究对象进行动三轴试验,研究在不同主应力比、围压和振动频率下浇筑式沥青混凝土的动力特性。分析结果表明,在不同主应力比、围压和频率下,心墙浇筑式沥青混凝土各动应力-应变骨干线变化规律基本相同,变化趋势与双曲线相符。围压与主应力比对动应力-应变骨干线的影响非常明显,而频率的影响很小。浇筑式沥青混凝土材料在各因素影响下的动弹性模量变化趋势也基本一致。在不同围压与主应力比下,最大动弹性模量公式计算值小于试验拟合值,最大相对误差分别达到16.6%和18.2%。因此,对动弹性模量表达式进行了修正,采用修正公式进行计算并与试验拟合值进行对比,两者结果较为吻合,最大相对误差分别减小到3.0%和2.0%。

A Multi-factor Study on Dynamic Characteristics of Pouring Asphalt Concrete

Pouring asphalt concrete core-wall dam has found wide application in Xinjiang due to its variety of advantages such as capability for construction under cold condition and good compatibility to deformation. As an earthquake-frequent area, Xinjiang faces an urgen issue for examining the anti-seismic performance of pouring asphalt concrete core-wall dam. The present work performed a dynamic triaxial experiment upon the anti-seepage material of a Xinjiang typical pouring asphalt concrete core-wall dam, in order to study the dynamic characteristics of pouring asphalt concrete under different principal stress ratios, confining pressures and vibration frequencies. The results showed that the variation law of all the dynamic stress-strain backbone curves of pouring asphalt concrete were basically identical and followed the hyperbolic variation trend while varying principal stress ratio, confining pressure and vibration frequency. The influence of confining pressure and principal stress ratio was very obvious to the dynamic stress-strain backbone curve, and the effect of vibration frequency was very small. The dynamic elastic modulus of pouring asphalt concrete also has basically similar variation trends in response to the above-mentioned multiple factors. We observed that the formula-calculated values of maximum dynamic elastic modulus were less than the test-fitting values under different confining pressures and principal stress ratios, and the maximum relative errors respectively reached 16.6% and 18.2%. Hence a modified dynamic elastic modulus expression was proposed, by which the dynamic elastic modulus was calculated and the resulted values coincided well (maximum relative errors respectively reduced to 3.0% and 2.0%) with the test-fitting values.