交通荷载作用下砾类土动本构关系试验研究

Experimental Study on Dynamic Constitutive Relationship of Gravel Soil under Traffic Loading

砾类土是新疆绿洲-荒漠区常用的一种路基填料,因此有必要研究其在交通荷载作用下的动本构关系。通过动三轴研究了不同工况时砾类土的动本构关系,发现可以采用R.L.Kondner双曲线模型对砾类土的动本构关系进行描述,并得出了不同工况时模型参数。基于试验结果分析了含水率、围压、压实度、初始静偏应力和循环荷载作用频率等因素对砾类土动本构关系的影响规律,得出了含水率和最佳含水率越接近,围压越大、压实度越高,砾类土动本构关系曲线越接近应力轴,初始静偏应力为0 k Pa和10 k Pa的动本构关系曲线较接近,动荷载作用频率为1 Hz和2Hz的动本构关系曲线也较接近。研究成果对新疆绿洲-荒漠区砾类土路基的应用具有重要的参考价值。

Gravel soil is a kind of commonly used subgrade filling in Xinjiang oasis-desert region,so it is necessary to study its dynamic constitutive relation under the traffic loading. Dynamic constitutive relationships of gravel soil under different conditions were studied through dynamic triaxial tests.It was found that dynamic constitutive relationship of gravel soil could be described by R.L.Kondner hyperbolic model, and then the model parameters under different conditions were obtained.The effect rules of water content, confining pressure, compaction degree, the initial static deviatoric stress and cyclic loading frequency on the dynamic constitutive relationship of gravel soil were studied based on the test results. The closer the relationship between moisture content and optimum moisture content, the greater the confining pressure, the higher the compaction degree, the dynamic constitutive relationship curve of gravel soil was closer to the stress axis. Dynamic constitutive relationship curve is relatively closer when the initial static deviatoric stress is 0 kPa and 10 kPa. It is also relatively closer when the dynamic load frequency is 1 Hz and 2 Hz.The study results have important reference value for the application of gravel soil subgrade in Xinjiang oasis-desert region.