【摘要】 有效围压、固结比、含砾量和颗粒破碎对砂砾土动剪切模量和阻尼比影响的规律已有较丰富的研究成果,但有关颗粒形状影响的研究鲜见报道。利用英国GDS公司的扭剪仪,对级配相同的圆砾砂砾土和角砾砂砾土进行动三轴对比试验,研究相对密度为45%,不同围压下颗粒形状对砂砾土动剪切模量和阻尼比的影响,发现:有效围压大于300 k Pa或剪应变幅值大于7×10-4时,圆砾砂砾土比角砾砂砾土具有更大的动剪切模量;对于最大动剪切模量,圆砾砂砾土和角砾砂砾土均存在砾石(粒径大于5 mm)含量P5的一个阀值P5cr,且角砾砂砾土的砾石含量阀值P5cr较圆砾砂砾土的大,当P5为阀值P5cr时,砂砾土的最大动剪切模量达到极大值;剪应变幅值大于2×10-4时,角砾砂砾土的阻尼比比圆砾砂砾土的大。更多还原

【Abstract】 The effects of effective confining pressure,consolidation ratio,gravel content and grain breakage on the shear modulus and damping ratio of gravel have been studied. However,only little work focused on the effect of the granule shape. Thus, the dynamic triaxial tests under different confining pressures were performed on the gravel specimens to investigate the effect of the granule shape on the shear modulus and damping ratio using a hollow cylinder apparatus(HCA), which is developed by GDS Instruments Ltd., United Kingdom. These specimens were made by two kinds of gravel(i.e.,with angular and round grains) with the same grain composition and relative density 45%. The results indicate that the gravel with the round shape has a higher shear modulus than that with the angular one when the confining pressure is higher than 300 k Pa or the shear strain amplitude is greater than 7×10-4. The gravel content(content of grains,whose diameter is bigger than 5 mm) corresponding to the maximum shear modulus is called the critical gravel content P5 cr,and the P5 cr of the angular sample is higherthan that of the round one. Conversely,the damping ratio of the angular sample is greater than that of the round one when the shear strain amplitude is larger than 2×10-4.更多还原