高速铁路基床底层泡沫轻质土填料试验研究

在松软土地基地区修建增建二线时,传统工法会对既有线造成较大干扰。为解决上述问题,引入一种新型路基填料泡沫轻质土。结合三轴试验结果,浇筑密度为600 kg/m^3的泡沫轻质土能满足高速铁路无砟轨道路基基床底层静动力条件要求,采用该材料取代常规基床底层填料,建立大比例室内模型试验。试验结果表明:采用泡沫轻质土材料填筑基床底层,路基结构可保证良好的动应力扩散效果,具有较大的刚度,保证较小的弹性变形(动位移),具有较小的塑性变形,保证较小的累积沉降值;该材料的综合作用能够保证轨道上部结构的平顺性,泡沫轻质土路基具有良好的动力特性和长期动力稳定性,能够满足高速铁路路基的长期服役要求。

Experimental study on foamed concrete as a filler of the bottom layer of high speed railway subgrade

When the additional second-line is built on the soft soil areas,interference problems for the existing lines would be caused by the traditional methods.In order to solve these problems,the foamed concrete used as a filler was introduced. According to the results oftriaxial tests,the foamed concrete with the casting density of 600 kg/m 3 can meet the static and dynamic conditions of the bottom layer of high-speed railway ballastless track subgrades. Using this material as the filler of the bottom layer of subgrade,large-scale indoor model tests were carried out. The results show that the subgrade structure has good dynamic stress diffusion effect when the foamed concrete is used as the subgrade filler. It has large stiffness and small plastic deformation,which guarantees small elastic deformation (dynamic displacement) and small cumulative settlement value. The foamed concrete subgrade has a good dynamic performance and long-term dynamic stability,and it can ensure the smoothness of subgrade surface,meeting the requirements of long-term service in high-speed railway.