列车荷载与水耦合作用下的无砟轨道水力劈裂机理分析

Hydraulic Fracturing Mechanism of Slab Track under Coupling Effect of Train Load and Water

针对高速列车荷载与水耦合作用下无砟轨道水致损伤问题,采用控制体积法推导层间裂纹内动水压力分布解析式,并开展裂纹内动水压力分布特性试验。试验结果与理论分析基本一致。采用有限元软件ANSYS与CFX,分析CRTSⅡ型板式无砟轨道层间裂纹内动水压力特性。结果表明:裂纹内动水压力由流体黏性、荷载特性、裂纹形状综合决定,当裂纹开口量大于2mm时,水的黏性对动水压力的影响可以忽略,此时动水压力与列车速度基本呈二次方关系,与轴重呈线性关系。分别采用最大拉应力准则和复合型断裂判据,分析列车荷载与水耦合作用下裂纹的扩展状态。结果表明:行车速度是影响裂纹扩展的重要因素,随着列车行车速度的增加,裂纹扩展速度明显加快。

With regard to the water-induced slab track damage under the coupling effect of high-speed train load and water,the analytic expression of the hydrodynamic pressure distribution in interlaminar cracks was derived using the control volume method,and the hydrodynamic tests were performed to analyze the pressure distribution.The experimental results were consistent with the theoretical results.The finite element software ANSYS and CFX were used to analyze the water pressure distribution in the cracks of Type CRTSⅡ continuous slab track.The results showed that the hydrodynamic pressure in the cracks was determined synthetically by the fluid viscosity,crack shape,and load characteristics.When the crack opening was greater than 2 mm,the effect of water viscosity on hydrodynamic pressure can be negligible.At this point,the value of hydrodynamic pressure was in linear relation to axle load and proportional to the square of train speed.The maximum tensile-stress criterion and mixed fracture criterion were used to analyze the propagation of cracks under the coupling effect of train load and water.The results showed that the train speed is an important factor affecting the crack propagation.The crack propagation rate increased with the increase of the train speed.