严寒地区路桥过渡段无砟轨道结构变形及损伤

以路桥过渡段CRTSⅢ型板式无砟轨道为研究对象,采用ABAQUS软件,建立非线性分析模型,基于混凝土塑性伤损理论,研究严寒地区路桥过渡段无砟轨道结构的变形及损伤。结果表明:过渡段冻胀变形对底座板损伤影响较大,而过渡段沉降变形对复合板(轨道板与自密实混凝土结合体)和底座板损伤均有影响;当过渡段长度较短时,冻胀变形导致的结构层间离缝在过渡段变形起始位置最严重;冻胀变形导致的结构层间离缝峰值较大,复合板与底座板、底座板与路基层间离缝的峰值分别为3.39和5.91 mm,而沉降变形导致的结构层间离缝范围较大;温度荷载与沉降变形共同作用导致底座板出现初始裂纹的沉降变形从沉降变形单独作用时的25.5 mm大幅减小到10.4~18.3 mm;温度荷载与冻胀或沉降变形共同作用复合板与底座板层间离缝峰值均发生在轨道板板缝处,分别为5.47和4.97 mm;当冻胀或沉降变形与在过渡段变形末端或变形起始点左侧的列车荷载共同作用时,底座板的损伤最为严重。

Structure Deformation and Damage of Ballastless Track of Roadbed-Bridge Transition Section in Severe Cold Region

The CRTSⅢslab ballastless track in roadbed-bridge transition section was taken as the research object.The nonlinear analysis model was established by using ABAQUS software.Based on the plastic damage theory of concrete,the deformation and damage of ballastless track in roadbed-bridge transition section in severe cold region were studied.Results show that the frost heave deformation in the transition section has great influence on the damage of base slab,while the settlement deformation has influence on the damage of both the composite slab(which is composed of track slab and self-compacting concrete)and the base slab.When the length of the transition section is short,the structural interlayer gap caused by frost heave deformation is the most serious at the initial position of the transition section.The peak value of the structural interlayer gap caused by frost heave deformation is larger.The peak values of the interlayer gaps between the composite slab and base slab,the base slab and subgrade are 3.39 and 5.91 mm respectively.But the range of the structural interlayer gap caused by settlement deformation is larger.The settlement deformation of initial cracks in the base slab caused by the joint action of temperature load and settlement deformation is greatly reduced from 25.5 mm under the action of settlement deformation alone to 10.4—18.3 mm.Under the combined action of temperature load and frost heave or settlement deformation,the peak value of the interlayer gap between the composite and base slabs mainly occurs at the expansion joint of the track slabs,which is 5.47 and 4.97 mm,respectively.When the frost heave or settlement deformation acts together with the train load at the end of the deformation or on the left side of the deformation starting point of the transition section,the damage of the base slab is the most serious.