【作者】 岳福青；

【导师】 杨春风；

【作者基本信息】 河北工业大学 ， 结构工程， 2004， 硕士

【摘要】 半刚性基层沥青路面的反射裂缝在我国高等级公路中普遍存在且难于防治。它严重影响了道路的使用寿命和行车安全。交通荷载和温度荷载是导致反射裂缝形成和扩展的主要因素。本文运用线弹性断裂力学理论对反射裂缝的扩展机理进行了全面分析，对基层预裂技术中合理切缝间距的确定方法进行了研究。 首先，对反射裂缝尖端应力场的奇异性进行了描述，建立了平面断裂问题应力强度因子的有限单元解。 其次，对含反射裂缝路面在交通荷载及温度荷载作用下的结构反应进行了深入分析。把交通荷载分为对称荷载和偏载两种情况，计算了裂缝尖端的拉应力、剪应力以及强度因子，并对路面结构进行了参数分析。对路面突然降温时的温度场进行了数值模拟，计算了温度应力作用下反射裂缝尖端的拉应力、应力强度因子，并对其进行了参数分析。而后对反射裂缝在行车荷载与温度荷载耦合作用下的裂缝扩展模式进行了研究。最后运用Paris公式对不同结构组合的路面进行了反射裂缝扩展速率的计算。分析计算结果表明，反射裂缝的扩展方式取决于裂缝尖端的受力情况，一般为复合型裂纹扩展。通过参数分析掌握了不同结构组合对反射裂缝扩展潜力及扩展速率的影响。 第三，在充分考虑到温度应力以及面层与基层、基层与土基之间的摩擦等因素后，建立了基层含预切缝路面的受力模型。通过结构参数分析掌握了预切缝间面层、基层中最大拉应力的分布规律。然后以预切缝上端应力强度因子、面层与基层内的最大拉应力为约束指标建立了合理预切缝间距的确定方法。更多还原

【Abstract】 Reflective cracking which seriously affect pavement fatigue life and driving safety is widely existed in our country’s highway and become into a hard problem to deal with. Traffic load and temperature load are two main factors accounting for its formation and propagation. In this paper, linear fracture mechanics is employed to give a full analysis to the mechanism of reflective crack’s propagation and the reasonable spacing of the induced crack technology is studied as well.Firstly, after depicting the singularity of stress field at the top of crack, the finite element method to calculate stress intensity factor of plain fracture problems is founded.Secondly, the structural response of pavement suffering reflective cracking is deeply analyzed in terms of traffic load and thermal load. As for traffic load, two situation were analyzed, symmetrical load and asymmetric load, in each of them, crack top’s tension stress, shear stress and stress intensity factor were calculated, also the effect of structural parameters were analyzed. Pavement’s temperature distribution field when suffering sudden temperature dropping was numerical simulated. Crack top’s tension stress and stress intensity factor caused by thermal stress were computed, structural parameters’ sensitivity analysis were made as well. Then, reflective crack’s propagation model under traffic load coupled with temperature load was analyzed. At last, reflective crack’s propagation speed of different pavement structural combination was analyzed too. The analyzing result indicated that reflective crack’s propagation model is decided by the stress at top of the crack, which often is a compound propagation model. By parameter analysis, reflective crack’s propagation potential and speed are also cleared.Thirdly, taking into account thermal stress, friction between surface and base and friction between base and soil, a mechanical model representing the pavement including induced crack is founded. The maximal tension stresses in surface and base between induced crack have been obtained by parametric analysis. Then, taking the maximal tension stress in surface and base and the stress intensity factor at the top of the induced crack as restraining indexes, method to determine the reasonable induced spacing has been determined.更多还原