基于黏聚力模型的双块式无砟轨道混凝土层间黏结性能试验与分析

Experimental Investigation on Adhesive Performance of Concrete Interface of Double-block Ballastless Track Based on Cohesive Zone Model

对双块式无砟轨道的层间黏结构件进行层间法向开裂和切向开裂模拟试验,依靠数字图像相关(DIC)技术获取了界面应力与分离位移的变化规律,并确定了用于层间开裂模拟的黏聚力模型关键本构参数。基于该黏聚力模型,运用有限元软件分析了构件层间法向和切向损伤开裂行为,并与试验结果进行了对比分析。结果表明:DIC技术能较好地描述双块式无砟轨道黏结构件从层间损伤,到裂纹萌生、扩展,再到裂纹贯穿于整个试件的全过程;黏聚力模型关键本构参数可保守地选取其法向黏聚强度为3.26 MPa,临界断裂能为12.2J/m2,切向黏聚强度为0.82 MPa,临界断裂能为4.5J/m2。有限元软件分析得到的界面应力与分离位移的变化规律与试验结果吻合较好,表明该黏聚力模型能较好地反映层间损伤开裂行为,为双块式无砟轨道层间损伤开裂机理研究提供了有效的理论分析工具。

Based on the normal and shear interface cracking experiments carried out on the interface bonded components from double-block ballastess track, the variation characteristics between the interface stress and relative displacements were obtained using digital image correlation （DIC） technique, and the key parameters of a cohesive zone model for simulating the interface cracking behavior were determined. Further, the damage and cracking behavior of the interface bonded components was analyzed using finite element software based on the cohesive zone model, and the simulation results were compared with those obtained by experiments. The results showed that the DIC technique can well describe the entire process from the interface damage development , crack initiation and propagation to complete failure of the interface bonded components from double-block ballastless track. The key constitutive parameters of the cohesive zone model can be conservatively selected with the bonding strength of 3.26 MPa, and the critical fracture energy of 12.2 J/m^2 in the normal direction, while for the shear direction, with the bonding strength and critical fracture energy of 0.82 MPa and 4.5 J/m^2 , respectively. The evolution law between the interface stress and relative displacements obtained by finite element analysis exhibited a good agreement with the experimental results, indicating that the proposed cohesive zone model can well reflect the interface cracking behavior, which provided an effective theoretical tool for investigating the interface damage mechanisms of double-block ballastless track.