煤矸石振陷变形特性试验研究

Experimental Study on Subsidence Deformation of Coal Gangue

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 residual strain under long-term dynamic load was an important reason for the vibration deformation of coal gangue roadbed. Based on laboratory dynamic triaxial tests, the cumulative residual strain and dynamic modulus were studied under different relative density and dynamic load amplitude conditions. The problems of the relative density and dynamic load amplitude were taken into account when the empirical formula of cumulative residual strain and dynamic modulus of coal gangue were established. The results showed that the relationship between cumulative residual strain and dynamic load amplitude was linear when the dynamic stress was less than the critical dynamic stress. The cumulative residual strain was unstable when dynamic stress was more than the critical dynamic stress. The increases in dynamic modulus of coal gangue with the decreases in the accumulation of residual strain followed the hyperbolic forms. The initial dynamic modulus increased with the increases in the relative density. The results would provide experimental and theoretical basis for the vibration deformation of coal gangue roadbed.