混凝土面板坝碎石垫层料最佳级配试验研究

Experimental study of optimum gradation of crushed stone cushion for concrete-face rockfill dam

混凝土面板坝碎石垫层料的最佳级配是d2 0 =0 2 5～ 1 5mm ,粒径小于 5mm的颗粒含量应在 30 %～ 6 0 % ,最大粒径为 40～ 10 0mm ,相对密度Dr>0 7,这时 ,碎石垫层料的渗透系数满足 (10 -3 ～ 10 -4 )cm/s数量级 ,且具有较高的抗剪强度 .设计垫层料的反滤层时考虑渗流方向向下 ,无需采用保护细料的原则 ,可直接用太沙基准则 .

The optimum gradation of crushed stone cushion for a concrete face rockfill dam is d 20 =0 25～1 5 mm, with a maximum grain size of 40～100 mm and a relative density of D r >0 7, containing 30%～60% in weight fine particles whose diameter is less than 5 mm. Thus, the permeability coefficient of the crushed stone cushion is of the order of (10 -3 ～10 -4 )cm/s, and the cushion has a high shear strength. Considering the downward direction of seepage in the filter design of the cushion, the rule protecting fine materials may not be used and Terzaghis criterion can be adopted directly.