基于多板协同受力的前嫩公路水泥混凝土路面应力有限元分析

Finite Element Analysis on Stress in Cement Concrete Pavement of Qiannen Highway Based on Multi-slab Co-stress

公路水泥混凝土路面板的侧面存在着三边约束、四边约束等多板协同受力情况,为此采用有接缝水泥混凝土路面三维有限元分析程序EverFE构建9块板的有限元验算模型,对前嫩(前锋农场—嫩江)公路嫩江支线一级公路水泥混凝土路面进行多板协同受力条件下的应力分析。结果表明:在多板协同受力时,面层板的最大弯拉应力与协同受力作用的强弱有关。当横缝设置传力杆后,板块之间的协同受力作用增强,横缝中部加载时,最大弯拉应力下降;纵向自由边中部加载时,最大弯拉应力有小幅度增长,验算条件下其增长幅度为1.3%以下。负温度梯度下,最大弯拉应力出现在面层板的表面,小于正温度梯度时的弯拉应力,同时其发生位置与正温度梯度情况不同,在加载板的荷载位置、面层板的中部都可能出现,且可能同时出现在多块板上;协同受力作用越强,其表现愈明显。板中加载时,协同受力强弱对面层板最大弯拉应力的影响较小。在零温度梯度情况下,基层刚度的下降将导致面层板最大弯拉应力的增大,此规律不受板块之间协同受力强弱的影响;非零温度梯度情况下,适当降低基层刚度对减小面层板的最大弯拉应力有利,且正、负温度梯度下的情况均相同。

Concerning the stress analysis for highway cement concrete pavements,various boundary conditions may apply,leading to multi-slab cooperative bearing scenarios involving 3-side constraint,4-side constraint,etc.To accommodate these scenarios,a 9-panel FE checking model is established by utilizing 3 D FE analysis program"EverFE"for stress analysing the cement concrete pavement on the Class-I branch of the Qianfeng Farm-Nenjiang Highway.The result shows that when multiple panels are co-working under stress,the maximum flexural stress in the pavement panel corresponds to the degree of co-working:(1)The addition of dowel bars in the traverse joints contributes to the degree of co-working,which in turn decreases the maximum flexural stress when the middle of the transverse joint is loaded.(2)For loads amid the longitudinal free edges,a minor increase of the maximum flexural stress is observed,which is below 1.3%under our calculation settings.(3)The maximum flexural stress appears on the surface of the pavement panel under a negative temperature gradient,at a level lower than that of a positive temperature gradient setting and at different locations,which could be at either the loading position of the loaded panel,or in the middle of the pavement panel,and might also appear simultaneously on multiple panels.The stronger the co-working effect,the more obvious the phenomenon.(4)When loading at the middle of the panel,the influence of the degree of co-working on the maximum flexural stress in the pavement panel is rather minor.(5)In the case of zero temperature gradient,decrease the stiffness of the base layer will lead to increased level of maximum flexural stress in the pavement panel.This rule is not affected by the degree of co-working between the panels.(6)In the case of non-zero temperature gradient,a slightly decreased base stiffness will benefit the reducing of the maximum flexural stress in the pavement panel.This holds true for both positive or negative temperature gradients.