摘要
为研究路基沉降对板式轨道轨面几何变形的影响,基于无拉力Winkler地基叠合梁理论,针对纵连式、单元式两种板式轨道,提出了考虑板底脱空的路基沉降与轨面变形间静态映射关系的计算方法,并对由不同沉降型式引起的两种轨道轨面变形特征及变化规律进行了对比分析.结果表明:纵连板式轨道对基础变形的适应力较单元板式轨道欠佳,底座板与路基间易形成大范围脱空;自重效应下沉降引起的两种轨道轨面变形随基础沉降量的增大差异加剧,且对路基沉降波长极为敏感,当沉降波长达到20 m后,轨下板底脱空现象明显缓解,轨面几何不平顺基本可与路基变形保持一致;路基折角型沉降对轨面平顺性的影响相对平缓,错台型沉降不仅使轨面剧烈弯折,还会导致板底严重脱空,10 mm差异沉降即可引发轨道与路基结构间约8 mm的空吊,给列车运营质量和轨道结构疲劳特性均造成不利影响.
In order to investigate the effect of subgrade settlement on the track geometry of the slab track,a calculation method for the mapping relationship between rail deflection and subgrade settlement was proposed,aiming at both longitudinal connected track and unit slab track of high-speed railways. The method is based on the theory of composite beams on tensionless Winkler foundation,which takes into account the potential voids between the bottom slab and the subgrade. The characteristics of the rail deflections of the aforementioned tracks,induced by different settlement profiles,were investigated and compared. The results show that in terms of the adaptability to the subgrade settlement,the longitudinal connected track is inferior to the unit slab track,while the largescale unsupported area is more likely to be induced between the longitudinal connected track and subgrade. The difference in rail deflection between the two tracks is significantly aggravated by the amplitude of the subgrade settlement. The rail deflection is also sensitive to the settlement wavelength.When the wavelength is extended to 20 m,the number of voids under the track are significantlyreduced and the rail deflection is basically in accordance with the subgrade. The influence of angulartype differential settlement on the deflection is relatively low,while the faulting-type settlement always results in severe rail deflection and voids. For instance, the maximum depth of void reaches approximately 8 mm when the faulting is 10 mm. The induced track irregularity and voids may pose threats to the train's operation quality and the fatigue behaviour of the track structure.
引文
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