中文摘要：

研究不同荷载作用下,高速铁路路基上双块式无砟轨道道床板空间力学特性。钢轨及道床板中钢筋用梁单元模拟,道床板、双块式轨枕、支承层以实体单元模拟,钢轨与道床板、道床板混凝土与钢筋、支承层与路基之间的连接用弹簧单元模拟,建立了可考虑混凝土开裂的路基上双块式无砟轨道三维有限元力学模型,分析了自重荷载、列车垂向荷载、不沉匀沉降荷载、温度梯度荷载作用下道床板的空间力学特性。结果表明：温度梯度荷载对混凝土纵、横向拉应力的影响最为显著;在列车荷载、不均匀沉降及温度梯度荷载作用下,钢筋纵向拉应力均超过了20 MPa;不同荷载作用下,支承层厚度、支承层弹性模量、道床板厚度等参数变化对混凝土和钢筋力学特性的影响不同;混凝土和钢筋纵向拉应力随着道床板裂缝间距的增加而增大。

英文摘要：

Study on spatial mechanical characteristics of track concrete layer of the twin-block ballastless track on subgrade under different loads.Rails and the steels in track concrete layer were simulated by beam element;the track concrete layer,the twin-block sleeper,the support layer were simulated by solid element;the connection between rails and track concrete layer,the concrete and the steels in the track concrete layer,the support layer and subgrade were simulated by the spring element.The three-dimensional finite element mechanical model of twin-block ballastless track on subgrade which considered the cracking of the concrete was established,the spatial mechanical characteristics of the track concrete layer under tare load was analyze,the vertical train load,differential settlement of subgrade load and tmperature gradient load was analyzed.The results show that temperature gradient load has the most significant impact on the longitudinal tensile force and the horizontal tensile force of the concrete.The longitudinal tensile force of the concrete all over 20 MPa no matter under the vertical train load,differential settlement of subgrade load or tmperature gradient load.Thickness of the support layer,elastic modulus of the support layer,thickness of the track concrete layer and other parameters have different impact on mechanical characteristic of the concrete and the steels under diffferent loads.The longitudinal tensile force of the concrete and the steels increases with the increase of the crack spacing.