铁路路基填料分类深化研究

根据泰波最大干密度理论和粒子干涉理论,分析不均匀系数取值范围及其对孔隙率的影响,提出颗粒级配的改进方案:当不均匀系数大于或等于10且曲率系数为1～3时,定义填料的颗粒级配为良好级配;当不均匀系数大于或等于10且曲率系数小于1或大于3时,定义填料的颗粒级配为间断级配;当不均匀系数小于10时,定义填料的颗粒级配为均匀级配。通过对影响填料工程性能因素的分析,并结合工程实践,提出填料分类分组的建议方案:在巨粒土和粗粒土中,细粒含量按5%,15%和30%分界;将细粒含量大于或等于15%的巨粒土和粗粒土划分为粉土块石、黏土块石、多粉土块石和多黏土块石等;对于细粒土,在粗粒含量大于或等于30%的条件下,将砾石含量大于或等于25%的细粒土定义为含砾液限土,否则定义为含砂液限土;巨粒土和粗粒土母岩的饱水抗压强度应大于或等于20MPa;在砾石类土划分中增加5mm粒组界限。

In-Depth Study on the Classification of Filling for Railway Subgrade

According to Talbol’s theory of maximum dry density and the theory of particle interference,the value range of nonuniformity coefficient and its effect on porosity were analyzed,the improved scheme for the gradation of particle size distribution was put forward.Good gradation is defined for filling particles when the nonuniformity coefficient is greater than or equal to 10,and the coefficient of curvature is between 1 and 3.Intermittent gradation is defined when the nonuniformity coefficient is greater than or equal to 10,and the coefficient of curvature is less than 1 or greater than 3.Uniform gradation is defined when the nonuniformity coefficient is less than 10.By analyzing the factors influencing the engineering performance of filling and combined with engineering practice,scheme for filling classification and grouping is proposed for railway subgrade.In giant-grained soil and coarse-grained soil,the boundaries of the fine content are divided by 5%,15% and 30%.The giant-grained and coarse-grained soil with the fine content greater than or equal to 15% is divided into silt boulder,clay boulder,multi-silt boulder and multi-clay boulder,etc.For fine-grained soil,under the condition that the coarse-grained content is greater than or equal to 30%,the fine-grained soil with gravel content greater than or equal to 25% is defined as liquid limit soil containing gravel,or else is defined as liquid limit soil containing sand.The water-saturated compressive strength of parent rock for giant-grained and coarse-grained soil should be greater than or equal to 20 MPa.5 mm particle fraction boundary is added in the division of the gravel soil.