脱空耦合下水泥混凝土路面疲劳寿命影响因素分析

Analysis of Factors AffectingFatigue Life of Cement Concrete Pavement under Void Coupling

基于ANSYS建立板底脱空的水泥混凝土路面力学模型,计算其在不同因素影响下的最大弯拉应力,分析其应力变化规律。然后,再利用公式计算板底脱空水泥混凝土路面不同因素下的疲劳寿命,分析其变化趋势,为水泥混凝土路面板设计及后期维护提出依据。最后,再结合疲劳寿命计算结果,利用层次分析法确定板底脱空状态下影响其疲劳寿命的各个主影响因素所占权重。结果表明：脱空半径对其影响最大,权重占0.483,且脱空半径达到400mm时,随着其他各因素的不利发展,疲劳寿命趋于稳定;温度梯度影响下,各脱空半径影响下的弯拉应力变化规律整体一致;面层模量对疲劳寿命影响相对较小,仅占0.114;面层厚度为300mm时,水泥混凝土路面性价比较高。

Based on ANSYS, a mechanical model of cement concrete pavement with void at the bottom of slab is established, and the maximum flexural tensile stress under different factors is calculated, and the variation law of stress is analyzed. Then, the fatigue life of cement concrete pavement under different factors is calculated by using the formula, and the changing trend is analyzed, which provides the basis for cement pavement design and later maintenance. Finally, combined with the calculation results of fatigue life, the weight of each major influence factor on the fatigue life of slab under the condition of void at the bottom of plate is determined by analytic hierarchy process （AHP）. The results show that the void radius of the largest influence on the weight, accounted for 0. 483, and the void radius reaches 400mm, along with the development of other adverse factors, the fatigue life tends to be stable; the effect of temperature gradient, the void radius of the bending stress of the overall variation; influence of surface layer modulus on fatigue life is relatively small,only 0. 114; and surface layer thickndss is 300mm, cement pavement has better economy.