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动荷载作用下累积轴向残余应变是煤矸石路基发生振陷变形的主要原因,利用自燃煤矸石原料制作圆柱形试件进行动三轴试验,研究了不同相对密度Dr、动荷载幅值σ_(dmax)条件下煤矸石累积轴向残余应变ε_(pa)和动模量E_d特性,建立了考虑相对密度、动荷载幅值二因素的累积轴向残余应变和动模量公式。试验结果表明:动应力小于临界动应力σ_(dcr)时,累积轴向残余应变与动荷载振次对数值log N呈线性关系,可用公式ε_(pa)=a+b log N进行计算;动应力大于临界动应力σ_(dcr)时,累积轴向残余应变呈加速增长形式;动模量随累积轴向残余应变增长而降低,呈双曲线形式;初始动模量随相对密度增加而增大。研究结果为煤矸石路基振陷变形分析提供了试验、理论依据。
The cumulative axial residual strain under dynamic load is the main reason for the coal gangue subsidence deformation. Using the self-ignited coal gangue raw material, a cylindrical specimen is made for the dynamic triaxial test. The effects of different relative density Dr, dynamic load amplitude σ_ (dmax), the cumulative axial residual strain ε_ (pa) and dynamic modulus E_d of coal gangue were calculated. The formulas of cumulative axial residual strain and dynamic modulus considering the relative density and dynamic load amplitude were established. The experimental results show that when the dynamic stress is less than the critical dynamic stress σdcr, the cumulative axial residual strain and the dynamic load-bearing vibration logarithm log N are linear and can be calculated by ε pa = a + b log N; When the stress is greater than the critical dynamic stress σdcr, the accumulated axial residual strain is in the form of accelerating growth. The dynamic modulus decreases with the increase of the cumulative axial residual strain and assumes the hyperbolic form. The initial dynamic modulus increases with the increase of relative density . The research results provide experimental and theoretical basis for the analysis of the deformation of coal gangue subgrade.