基于骨架孔隙比的土石混合料强度变形特性

Strength and deformation characteristics of soil-rock mixtures using skeleton void ratio

土石混合体是由具有一定尺寸石块、作为充填成分的土体及孔隙等组成的混合体,其强度变形特性与细粒(土粒)含量密切相关。为研究不同细粒含量土石混合料强度变形特性,建议采用以承担骨架作用的颗粒的孔隙比(骨架孔隙比)反映土石混合料内部真实密实情况。开展了系列压实试验,建立了考虑土石级配的土石混合料堆积模型,进而推导了土石混合料骨架孔隙比表达式,并通过室内三轴排水剪切试验,验证了骨架孔隙比用以预测土石混合料强度变形特性的有效性。结果表明:相较于常规定义的整体孔隙比,骨架孔隙比能更好地表示土石混合料内部颗粒接触状态,反映材料内部“真密实”情况;利用骨架孔隙比概念,可以仅由纯石/土料强度变形特性预测不同细粒含量的土石混合料强度变形特性。

The soil-rock mixture(SRM)is composed of large-sized rocks,soils as filling component and pores.The strength and deformation characteristics of SRM are closely related to its fine contents(soil contents).The skeleton void ratio,referred to as the void ratio of skeleton particles,is proposed to study the strength and deformation characteristics of SRMs with different fine contents.Firstly,a series of compaction tests was performed to establish a packing model for SRM accounting for gradation effects,from which the expression of skeleton void ratio was derived.Triaxial drained tests were also conducted to verify the effectiveness of the proposed skeleton void ratio in predicting the strength and deformation characteristics of SRMs with different fine contents.It is found that the skeleton void ratio,compared with global void ratio,can better reflect the real density of soil-rock mixture by revealing the intergrain contact state of soil and rock particles.The mechanical behavior of soil-rock mixtures with different fine contents can be reasonably predicted by testing pure soils or rocks.