级配缩尺对堆石压缩特性影响试验研究

选用两项工程筑坝堆石材料,将原级配堆石料按不同的缩尺方法和不同最大控制粒径进行缩尺,并对同种堆石材料选取相同的相对密度控制指标,研究了缩尺后堆石材料压缩特性的变化规律和级配特征对压缩特性影响规律。结果表明:缩尺后堆石材料的压缩模量随缩尺后最大粒径和各特征粒径的增大而减小,粒径增大约3倍,压缩模量减小幅度可达约1/2,随原级配最大粒径的增加,缩尺后材料的控制粒径对压缩模量的影响更为显著;缩尺后材料级配的不均匀系数越大,压缩模量越小,曲率系数越大,压缩模量越高,采用等量替代法缩尺获得的堆石材料压缩模量随粒径增大的减小幅度大于采用相似级配法后的值。对于不同的堆石材料,由于母岩岩性以及材料原级配等方面存在差异,研究成果有待更多验证。

Experimental study of grading scale effect on compression properties of rockfill material

By adopting two engineering rockfill materials for dam construction， the original grading rockfill materials are scaled down with various reduced-scale methods and various control particle sizes， and then both the changing law of the compression properties and the law of the influence from the grading characteristics on the compression properties of the rockfill materials after the scale reduction are studied on the same kinds of rockfill materials by selecting the same control indexes of the relative density. The result shows that the compressive modulus of the rockfill material after the scale reduction is decreased along with the increases of the maximum particle size and all the characteristic particle sizes， from which the particle size is increased by about three times， while the decreasing amplitude of the deformation modulus can reach to about 1/2.Following the increase of the maximum original grading particle size， the influence from the control particle size on the compressive modulus is more significant after the scale reduction of material. The larger the uneven coefficient of the material after the scale reduction is， the less the compressive modulus is to be， while the larger the curvature coefficient is， the higher the modulus is to be. The amplitude of the decrease along with the increase of the particle size of the compressive modulus of the rockfill material obtained through the scale reduction made by the equivalent replacement method is larger than the value got from the similar grading method. For various rockfill materials， this study result is to be further verified due to the differences in the aspects of lithology of the source rock， the original gradation of material etc.