Gradation equation of coarse-grained soil and its applicability

粗粒料的级配方程及其适用性研究

Gradation equation is one way to describe the gradation of coarse-grained soil conveniently,exactly and quantitatively.With the gradation equation,the influence of gradation on the mechanical behaviors of coarse-grained soil can be expressed quantitatively.A new gradation equation with a parameter is proposed.The basic properties and applicability of the new equation are studied.The results show that the proposed equation has the applicability to express coarse-grained soil gradation(CSG),and the range of the parameter β is found to be 0<β<1.The value ofbdetermines the gradation curve shape.If β>0.5,the gradation curve is sigmoidal,otherwise the gradation curve is hyperbolic.For well graded gradations,the parameter has the value of 0.13<β<1.Several CSGs used in domestic and foreign earth-rockfill dams are probed,and the value of the parameterbfalls in the range of 0.18 to 0.97.The investigation of the range of β is of value to guide the design for CSG of earth-rockfill dam.

级配方程可以准确和定量地表示粗粒料的级配,级配方程使得定量研究粗粒料级配与其物理力学性质之间的关系成为可能。提出了一个适用于描述粗粒料连续级配的级配方程,并对该级配方程的基本性质和适用性进行了研究。结果表明:提出的级配方程对粗粒料的级配具有良好的适用性。方程参数β的范围为(0,1),参数的大小决定了级配曲线的类型。当β大于0.5时,方程表示的级配曲线为反S形,否则为双曲线形。当β为0.13~1时,方程表示的级配为良好级配。对国内外土石坝用粗粒料的级配曲线进行了探讨,其参数值为0.18~0.97。该范围的确定对土石坝用粗粒料级配的设计具有指导价值。