FAILURE CRITERIA AND LATERAL STRESSES IN TRACK FOUNDATIONS
FAILURE CRITERIA AND LATERAL STRESSES IN TRACK FOUNDATIONS
复制标题
轨道基础的失效准则和横向应力
DOI：
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
G. M. Norman‐Gregory
中科院分区：
文献类型：
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作者：
H. E. Stewart;E. Selig;G. M. Norman‐Gregory
在传统的轨道系统中，枕木由底层道碴或路基或两者下方的未粘合道碴层支撑。用于估计这些多层系统的应力和变形的分析模型预测，未结合层的下部将产生显着的增量拉伸应力。它们的大小与通常预期的地静应力相结合，可以预测道碴的故障。一些分析模型已纳入未结合层的失效准则，作为将这些应力限制在允许值的手段。讨论了这些方法以及预测失效对永久变形预测方法的影响。提出了一种基于道碴中残余侧向应力的替代方法。描述了用于测量残余侧向应力的实验室箱式测试装置。实验结果表明，由于反复施加载荷，道碴中会产生相对较大的残余应力。讨论了将未结合层中的初始应力与连续体或有限元模型预测的增量拉伸应力相结合的效果。特别关注这些残余应力对永久变形预测的影响。
In conventional track systems the ties are supported by an unbound ballast layer underlain by subballast or the subgrade, or both. Analytical models used to estimate stresses and deflections of these multilayer systems predict that the lower portions of the unbound layer will develop significant incremental tensile stresses. Their magnitude is such that, when combined with the normally expected geostatic stresses, failure of the ballast is predicted. Some analytical models have incorporated failure criteria for the unbound layer as a means of limiting these stresses to permissible values. A discussion of these approaches is presented along with the implications that predicted failure would have for permanent deformation prediction methodologies. An alternative method based on residual lateral stresses in the ballast is presented. A description is given of a laboratory box testing device used to measure residual lateral stresses. Experimental results are shown that indicate that relatively large residual stresses, due to repeated applications of loading, can develop in ballast. The effects of combining the initial stresses in the unbound layer with the incremental tensile stresses predicted by continuum or finite element models are discussed. Particular attention is given to the effects that these residual stresses have on prediction of permanent deformation.