水泥混凝土路面设计极限状态方程的研究

Study on the design limit state formula for cement concrete pavement

在原《公路水泥混凝土路面设计规范》(JTG D40—2002)设计极限状态方程的研究基础上,对新颁布实施的《公路水泥混凝土路面设计规范》(JTG D40—2011)设计极限状态方程进行深入研究,进一步探讨设计极限状态方程中的疲劳应力与极限应力的力学概念问题。根据原规范(JTG D40—2002)设计极限状态方程的研究结论,对新规范(JTG D40—2011)设计极限状态方程中的荷载力与温度力、疲劳应力与极限应力、设计验算极限弯拉强度及疲劳修正系数等问题进行力学分析,提出存在的问题。采用同济大学研究的水泥混凝土试验疲劳方程,通过水泥混凝土路面的实际受力状态及疲劳应力等力学研究,对新规范(JTG D40—2011)设计极限状态方程进行修正,提出合理的新规范(JTG D40—2011)设计极限状态方程修正公式。通过修正公式与新规范(JTG D40—2011)公式的对比设计,对比结果说明修正公式更加科学合理,论证修正极限状态方程的正确性。研究结果表明,新规范(JTG D40—2011)公式的设计板厚偏小,修正公式更符合水泥混凝土路面的设计要求。

Based on the design limit state formula in the specifications of cement concrete pavement design for highway（ JTG D40—2002）,an in-depth study was carried out on the design limit state formula in the new specifications（ JTG D40—2011）,and furthermore,some mechanical concepts such as the fatigue stress and the limit stress in the limit state formula were discussed. According to the conclusions drawn from the limit state formula in the original specifications（ JTG D40—2002）,the problems associated with the limit state formula in the new specifications（ JTG D40—2011）,including the vehicle force and thermal force,fatigue stress and the limit stress,the design limit bending and tensile strength of concrete and the modified fatigue coefficients,etc.,were analyzed and then the existing problems were described. By applying the fatigue formula of concrete developed in Tongji University and studying the practical stress state and fatigue stress of the cement concrete pavement,the design limit state formulas in the new specifications（ JTG D40—2011） were modified,and the modified design limit state formula were then put forward in the new specifications（ JTG D40—2011）. Through the comparative design between the modified formulae and the formulae in new specifications（ JTG D40—2011）,the results indicated that the modified formulae were more reasonable,validating the effectiveness of the modified design limit state formula. The research results show that the design thickness of concrete slab according to the new specifications（ JTG D40—2011） formulae is smaller,while the modified formulae may meet the design requirements of the cement concrete pavement.