粗粒土颗粒破碎大型直剪试验研究

Large-scale Direct Shear Experimental Study on Particle Breakage of Coarse-grained Soils

颗粒破碎是粗粒土的基本属性。随着高土石坝的陆续兴建,高应力下粗粒土的颗粒破碎特征成为人们研究的一个重要方面。通过对不同粒径粗粒土试样的大型直剪试验,研究了高法向应力下粗粒土的颗粒破碎规律,并对接触面剪应力-剪位移关系进行了分析。结果表明:随着法向应力增加,颗粒破碎率增加;相同法向应力下,粒径越大,破碎率越大;级配越良好,破碎率越小;颗粒破碎主要形成次一级粒径。

Particle breakage is the basic property of coarse-grained soils. With the continuous construction of high earth-rock dams, the characteristics of particle breakage of coarse-grained soils under high stress are one of the important aspects for the particle breakage study. The large-scale direct shear tests were performed on the coarse-grained soils with different particle sizes to investigate the characteristics of particle breakage of coarse-grained soils under high normal stress, and the relationship be- tween the shear stress and shear displacement at the interface was also analyzed. The results suggested that （1） with the in- creasing of normal stress,the particle breakage rate increases; （2） under the same normal stress, the particle breakage rate is higher when the particle size is higher; （3） the better the grading is, the lower the breakage rate is; and （4） the particle breakage mainly forms the sub-first grade particle size.