Foam light soil is widely applied in highway subgrade, but not in high speed railway subgrade.Here, a new-type anti-vibration roadbed material of foam light soil was proposed to be applied in high speed railway subgrade.The influences of wet density of foam light soil on its compressive strength were studied under different curing periods through deeply studying its density, strength and stress-strain characteristics combined with its uniaxial compression tests.The traditional and new-type high speed railway subgrade models were established by using FE software, the material parameters were obtained with laboratory tests and data investigation.The train moving loads were simulated with a beam-elastic half-space model, and a comparative study was conducted for dynamic responses of foam light soil and traditional roadbed material applied in high speed railway subgrade, respectively.The results showed that there is a good correlation between wet density and compressive strength of foam light soil;foam light soil''s compressive strength increases with increase in its curing period, its compressive strength increasing rate is larger firstly, then smaller;compared with those of the traditional subgrade, dynamic stresses of surface layer, filling, and foundation of the new type subgrade decrease to a certain extent, the vibration reduction capabilities of surface layer and filling of the new type subgrade are bigger obviously, their vibration reduction amplitudes are 3.75 kPa and 2 kPa, respectively, the vibration reduction amplitude of the subgrade foundation is 0.78 kPa;but, the vibration reduction amplitude of the traditional roadbed is bigger than that of the new-type one by 3.5 kPa, so foam light soil is not recommended to be applied in the bottom layer of subgrade;generally speaking, foam light soil has a great potential in the field of high speed railway subgrade, the results can provide a reference for studying the further vibration reduction of high-speed railway subgrade.%泡沫轻质土在公路路基上应用广泛,但尚未在高速铁路路基上应用.提出一种泡沫轻质土的高速铁路新型减振路基材料.通过对其密度,强度,应力应变特性进行深入探究,结合单轴压缩试验,研究不同养护龄期下的泡沫轻质土湿密度对抗压强度的影响.采用有限元软件建立传统材料和新型材料下的高速铁路路基模型,通过室内试验和资料调研得到材料参数,梁-弹性半空间模型模拟列车移动荷载,并将泡沫轻质土与传统路基材料在高速铁路路基上应用时分别产生的动响应进行对比研究.结果表明,泡沫轻质土的抗压强度与湿密度之间具有良好的相关性,抗压强度随着养护龄期的增长而增大,且早期增长较快,后期增速逐渐降低.相对于传统路基,新型路基基床表层、基床填土和地基基础的动应力都有一定程度的减弱,其中基床表层和基床填土的减振能力最为明显,消减幅度分别为3.75 kPa和2 kPa,地基基础相对减振0.78 kPa.但在基床底层减振方面,传统路基材料反而比新型路基材料在基床底层上减振3.5 kPa,故不建议将新型材料应用于基床底层.综上,泡沫轻质土在高速铁路路基领域具备很大的发展潜力,研究成果可为高速铁路路基的进一步减振研究提供参考.
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