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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。
The space mechanical properties of double-block ballastless track bed on high-speed railway subgrade under different loads are studied. The simulation of the beam element of steel bar in the rail and track bed board, the simulation of the bed board, the double-block sleeper and the support layer by the solid unit, the connection between the rail and the track board, the track bed board concrete and the steel bar, The three-dimensional finite element model of two-block ballastless track on the embankment which can consider cracking of concrete is established. The spatial mechanical characteristics of ballastless slab under self-weight load, train vertical load, non-uniform settlement load and temperature gradient load are analyzed. The results show that the temperature gradient load has the most significant influence on the longitudinal and transverse tensile stresses of the concrete. The longitudinal tensile stress of the reinforced concrete exceeds 20 MPa under the loads of the train, uneven settlement and temperature gradient. Under different loads, the thickness of the support , The elastic modulus of support layer and the thickness of ballast bed have different effects on the mechanical properties of concrete and rebars. The longitudinal tensile stress of concrete and rebar increases with the increase of cracks in ballast bed.