Deformation characteristics of fresh and fouled ballasts subjected to tamping maintenance
Deformation characteristics of fresh and fouled ballasts subjected to tamping maintenance
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DOI：
10.1016/j.sandf.2016.07.006
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发表时间：
2016-08-01
影响因子：
3.7
通讯作者：
Hayano, Kimitoshi
中科院分区：
文献类型：
--
作者：
Kumara, Janaka J.;Hayano, Kimitoshi
随着时间的推移，大量的火车通行会导致有碴铁路轨道的大沉降。在世界范围内进行夯实维护的应用，可能会导致由夯实工具引起的干扰导致额外的后续轨道沉降。在本研究中，在按比例缩小的有碴铁路轨道上进行了一系列模型试验，以研究夯实维修应用下碴体的沉降特性。采用颗粒图像测速法（PIV）跟踪了循环加载过程中颗粒的运动，研究了夯具引起的局部变形。结果表明，污垢物质的侵入和后续的维护使沉降特性发生了显著变化。PIV结果显示，顶压舱被夯实工具松动。同时还发现，压舱物的强度性能随着材料的污染而下降。值得注意的是，根据污垢指数FIp（即污垢程度的指示），当材料经历30%或更多的污垢时，压载物的应变硬化行为减弱。研究结果表明，在FIp达到30%之前，应对受污染的道砟进行夯实。(C) 2016日本岩土工程学会。制作和托管由爱思唯尔B.V.
A number of train passes over time induces large settlement on ballasted railway tracks. Tamping maintenance application, which is practised worldwide, can lead to additional subsequent track settlement from the disturbances caused by the tamping tools. In this study, a series of model tests on a scaled-down ballasted railway track was conducted to examine the settlement characteristics of ballast subjected to tamping maintenance application. The particle movements during cyclic loading were tracked using a particle image velocimetry (PIV) approach to study the local deformations induced by the tamping tools. The results revealed that the intrusion of fouling material and subsequent maintenance application altered the settlement characteristics significantly. The PIV results revealed that the top ballast is loosened by the tamping tools. It was also found that the strength properties of ballast deteriorate with the fouling of the material. Notably, the strain hardening behaviour of ballast is weakened when the material undergoes 30% fouling or more according to the fouling index, FIp (i.e., an indication of degree of ballast fouling). The results of this study suggest that track maintenance should involve the tamping of fouled ballast before FIp reaches 30%. (C) 2016 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V.