基于堆积试验的道砟级配对休止角的影响

Influence of Ballast Grading on Repose Angle Using Experimental Pouring Test

采用漏斗法对不同级配的铁路道砟开展室内堆积试验,探究颗粒级配参数对堆积体休止角的影响。参照现行特级道砟规范,设计了4组均匀级配和18组非均匀连续级配,通过图像处理技术提取道砟堆的轮廓线,拟合后测得休止角。结果表明,随着中值粒径D_(50)的提高,D_(50)=37.6mm时休止角存在最大值;随着不均匀系数C_(u)的增加,休止角在C_(u)=2.1时存在最大值,可认为C_(u)=2.1、D_(50)=37.6mm是优良的道砟级配参数;级配曲线的曲率C_(c)在0.88左右时,道砟堆积体休止角存在峰值。研究结果对现行特级道砟的级配优化具有一定参考价值。

The fixed funnel method was used to measure the repose angle of ballast pile with different gradations to investigate the effect of gradation parameters on the repose angle of ballast.Four ballast samples of uniform size distribution and 18ballast samples of uneven gradation were prepared.The contour lines and the repose angles of ballast pile were obtained with image processing technology.The results show that,with the increase of median particle size D_(50),the angle of repose has a maximum value when D_(50)=37.6mm,with the increase of non-uniformity coefficient C_(u),the angle of repose has a maximum value when C_(u)=2.1.It can be considered that C_(u)=2.1is the best non-uniformity coefficient of well grading.When the curvature of grading curve C_(c) is about 0.88,the repose angle of ballast pile reaches a peak value.The research results provide some insights into the optimization of the grading parameters in the ballast specification.