基床翻浆冒泥土的物理力学性质

Physical and Mechanical Properties of Mud Pumping Soils in Railway Subgrade Bed

随着列车提速和轴重大幅增加,基床出现翻浆冒泥病害的几率加大.为了进一步研究翻浆冒泥发生机理和探究其发生条件,系统研究了60多组翻浆冒泥实例,分析了翻浆冒泥土的颗粒组成、可塑性指标、渗透性及矿物成分等物理力学性质.研究结果表明:翻浆冒泥土中,绝大部分黏粒含量大于20%、粉粒含量大于20%,黏粒含量大于30%和粉粒含量大于40%的土所占数量最多;翻浆冒泥土中粉粒的含量一般要高于黏粒含量;翻浆冒泥土(主要包括砂黏土、粉质黏土、黏土和部分低液限粉质黏土)液限大于23%,塑性指数大于6.5;翻浆冒泥土渗透系数小于1.0×10^(-5)m/s;翻浆冒泥土的渗透系数与细颗粒含量之间存在较好的负指数关系.

Substantial increase in train speed and axle load may result in an increase in the probability of occurrence of the mud pumping problem in subgrade bed. In this study,to further study the mechanisms and occurrence conditions of the mud pumping problem,more than 60 mud pumping samples reported in published literature were studied systematically. Further, the physical and mechanical properties of mud pumping soils, such as particle composition, plasticity index,permeability,and mineral composition were analysed and summarized. The results indicate the following： For the most mud pumping soils,clay and silt particle content is greater than 20%; soils with clay content greater than 30% and silt content greater than 40% account for the largest proportion of the samples. In mud pumping soils,the silt content is generally greater than the clay content. The liquid limit is more than 23%,and plasticity index greater than 6. 5,i. e.,sandy clay,silty clay,clay and part of low liquid limit silty clay. Generally,the permeability coefficient of mud pumping soils is less than 1. 0 × 10^（-5）m/s. The permeability coefficient and fine particle content show good negative exponential correlation.