为研究沥青铺装层温度效应对正交异性钢桥面板焊接细节疲劳性能的影响,本文基于线弹性断裂力学,研究了铺装层温度效应对焊接细节应力及顶板焊趾处疲劳裂纹尖端应力强度因子的影响规律,并基于 XGBoost算法建立了裂纹修正系数预测模型。研究表明：沥青铺装层厚度及其温度效应对钢桥面板焊接细节疲劳性能的影响不可忽略；高温情况下,顶板焊趾处的疲劳裂纹扩展速率较快,裂纹形态比对有效应力强度因子的影响更大,仅通过应力评估铺装层温度效应对钢桥面板焊接细节疲劳性能的影响偏不安全；顶板焊趾处的应力及裂纹尖端的有效应力强度因子与铺装层温度效应呈非线性相关；结合本文建立的裂纹修正系数预测模型可以有效预测疲劳裂纹尖端的有效应力强度因子,便于工程中对温度影响下的焊接细节疲劳性能进行快速评估。

In order to study the effect of temperature effect of asphalt pavement on the fatigue properties of welding details of orthotropic steel bridge deck, based on linear elastic fracture mechanics, this paper studied the effect of temperature effect of asphalt pavement on the stress of welding details and the stress intensity factor of fatigue crack tip at the weld toe of the roof, and established a crack correction coefficient prediction model based on XGBoost algorithm. The results show that the influence of asphalt pavement thickness and temperature effect on the fatigue properties of welded details of steel bridge deck cannot be ignored. Under high temperature conditions, the fatigue crack propagation rate at the weld toe of the roof is faster, and the crack shape ratio has a greater influence on the effective stress intensity factor. It is unsafe to evaluate the effect of pavement temperature effect on the fatigue performance of welded details of steel bridge deck only by stress. The stress at the weld toe of the roof and the effective stress intensity factor at the crack tip are nonlinearly related to the temperature effect of pavement layer. Combined with the prediction model of crack correction coefficient established in this paper, the effective stress intensity factor of fatigue crack tip can be effectively predicted, which is convenient for rapid evaluation of fatigue properties of welding details under the influence of temperature in engineering.

U448.3

国家自然科学基金项目（面上项目，重点项目，重大项目）