路面板早龄期固化应力形成与松弛的三维全时程仿真与机制研究

Cement concrete pavement take advantage of local materials easily, and has wide application in China. However, the problem of premature breakage due to heavy traffic significantly restricts the widespread use of cement concrete pavements in recent years. The theory of early age construction shows that condensation curing and hardening of concrete early age behavior will form a specific initial pavement characteristics, and it could contributes to the complex or premature destruction of pavement slabs. At present related research is in the ascendant. Based on the previous studies on built-in curling, this project intends to further and more deeply study the mechanism and influence of the formation and relaxation of built-in stress under the combined effect of temperature and humidity non-uniform field and structural constraints. Firstly, it focuses on the condensation and modulus module simulation considering the three-dimensional distribution of non-uniform characteristics of the full slab, and then integrates with the foundation program of the early age simulation of the pavement slab to realize the three-dimensional full-time numerical simulation of the formation and relaxation of the built-in stress. Designed stress monitoring method and high-precision fiber grating displacement sensor, the three-dimensional full-slab observation of stress in the early age can be observed. The formation mechanism and characterization of the built-in stress in the early age were studied. Base on the made of intermediate parameters, the influence of built-in stress on the bearing capacity of pavement during service period was researched in combination with the vehicle loading. And the design and analysis methods are put forward in order to provide support for the pavement analysis and design theory and construction technology improvement.

水泥混凝土路面容易就地取材，在我国有着广泛应用，但近十几年来的发展一直困扰于重载交通过早断板问题。施工早龄期研究显示，混凝土早龄期的凝结固化及硬化行为会形成特定的路面板初始性状，进而促成路面板的复杂或过早破坏，但目前相关研究仍处于起步阶段。本项目在前期固化翘曲研究基础上，拟进一步更细致深入地关注温湿度时程不均匀场和结构约束共同作用下固化应力形成与松弛机制及其影响研究。首先重点攻关考虑全面板三维分布不均匀特性的凝结固化和模量模块仿真，然后与路面板早龄期仿真基础程序进行拼装整合，实现固化应力形成与松弛的三维全时程数值仿真，并结合专门研制的应力监测装置和高精度光纤光栅位移传感器，进行早龄期应力的三维全面板时时观测，深入开展早龄期固化应力形成机制和性状特征研究，构造中间参数与车辆荷载作用进行结合，开展固化应力对路面服役期承载性能影响研究，并提出设计分析方法，以为路面理论提升、施工技术改善提供支持。

研究显示，路面板早龄期固化应力可能引起面板强度折减和脆性断裂、改变路面板的破坏模式。由于相关理论研究时间较短，目前早龄期固化应力的行为特征、形成机制与影响效应还未得到充分研究和揭示。鉴于此，项目针对路面板早龄期固化应力形成与松弛机制及其影响开展系统研究。首先重点攻关考虑全面板三维分布不均匀特性的凝结固化和模量模块仿真，编制考虑温湿度条件影响的微预应力-固结理论徐变模型模块，与路面板早龄期仿真基础程序进行拼装整合，实现三维全时程路面板早龄期力学行为数值仿真；采用无应力圆筒装置基于应变历史结合步进法，提出现场试验监测路面板早龄期应力的试验方法，开展了早龄期应力监测现场试验和程序验证；基于自编程序，对路面板早龄期应力及固化应力场性状特征、形成机制进行了深入揭示，研究了早龄期应力与交通荷载共同作用下路面板复杂断板破坏模式和机制，并进行了工程应用。.取得的主要研究成果有：（1）集成开发了三维路面板不均匀力学行为数值仿真程序，程序综合考虑了水化热、外界环境、施工工艺、结构型式与约束以及三维非均匀固化硬化演化特征等因素影响。程序采用基于微预应力-固结理论的徐变模型，可对路面三维结构早龄期徐变效应机制、徐变效应的参数影响规律和敏感性进行揭示，厘清了徐变对路面早龄期固化应力形成与松弛的影响机制和早龄期徐变的参数影响效应。（2）采用无应力圆筒装置，基于应变历史结合步进法考虑徐变的影响，通过理论结合试验获得了路面板早龄期应力典型性状与时程特征。（3）基于建立的路面板早龄期仿真程序，系统地揭示了路面板早龄期应力全时程行为、典型应力性状特征，参数影响效应和敏感性。提出了复合应力场和固化应力场概念，建立了早龄期应力场特征矩阵，得到了不同施工环境场与结构型式路面板固化应力场典型分布型式和性质。（4）基于自编仿真程序，结合交通荷载考虑路面板早龄期固化全时程，分析研究了路面板在复合应力场与交通荷载共同作用下的应力性状和参数影响特性；建立固化应力场与复合应力场的简化等效参数，结合XFEM拓展有限元技术，揭示了路面板在复合应力场与交通荷载共同作用下断板开裂模式，并基于理论研究提出了早龄期应力的工程控制对策和分析方法。.基于以上，项目较为系统地对水泥路面板早龄期应力形成机制与影响效应开展了理论研究，研究成果成功应用于水泥混凝土路面板加铺改建、机场道面结构设计、道面板状态与断板诊断等多个领域，理论价值显著。