双向交通荷载作用下粉煤灰土动力特性研究

针对传统的粉煤灰土动力特性研究中只考虑单向荷载作用的局限性，将交通荷载简化为双向振动的正弦波形循环荷载，采用FST-200型动三轴试验机进行双向交通荷载作用下粉煤灰土的动三轴试验，分析了径向动应力对粉煤灰土轴向累积塑性变形、动强度和动弹性模量的影响，建立了轴向累积塑性变形与振动次数关系的分段函数数学模型。结果表明：在双向交通荷载作用下，粉煤灰土的轴向累积塑性变形与振动次数、轴向动应力幅值正相关，与径向动应力幅值负相关，施加径向动应力降低了动偏应力，提高了土样的刚度，使轴向塑性累积变形减小；粉煤灰土的动强度、动弹性模量随径向动应力的增加而增大，随振动次数增加而降低；建立的数学模型能够反映粉煤灰土在双向交通荷载作用下的动变形特性。

Study on Fly Ash Soil Dynamics Characteristics under Two-way Trafifc Load Effect

Considering the limitation that traditional researches on lfy ash soil dynamics characteristics only consider one-way load effect, the paper simpliifes trafifc load to two-way vibrating cyclic load with sine waveform, uses FST-200 dynamic tri-axial test machine for dynamic tri-axial test of lfy ash soil under the effect of two-way trafifc load, analyzes the inlfuence of radial stress on the axial accumulated plastic deformation, dynamic strength and dynamic elastic modulus of lfy ash soil, establishes piecewise function mathematics model of axial accumulated plastic deformation. The research shows that under the effect of two-way trafifc load, axial accumulated plastic deformation has positive relevance with vibration times and axial dynamic stress amplitude, and negative relevance with radial stress amplitude, implementing radial dynamic stress reduces dynamic deviatoric stress, increases the rigidity of soil sample, reduces axial accumulated plastic deformation; dynamic strength and dynamic elastic modulus increase along with the increase of radial dynamic stress, reduce along with vibration times; the established mathematics model can relfect the dynamic deformation characteristics of lfy ash soil under two-way trafifc load effect.