深部高应力-温度-渗透压耦合下超高性能混凝土损伤演化和传输机理

The exploration into the underground has become inevitable for human beings to expand the living space in the future. The concrete damage and structural performance degradation are greatly affected in the harsh environment deep underground. Focusing on the three prominent features (high stress, high temperature and high osmotic pressure) in the service environment of deep engineering structures, this project adopts the thermodynamics and porous media mechanics theory as well as the modern testing technology to characterize the macro, meso, microstructure and defect evolution parameters of the ultra-high performance concrete, to reveal the mechanism of ions transport, enrichment, adsorption, solidification and water flow and to develop the spatiotemporal evolution and distribution law of the deep stress field - temperature field - seepage field coupling. Based on this, considering the combination of damage accumulation and multiple ions interaction, the numerical transport model of micro-meso-marco scale, under the synergic condition by multiple field and multi-ions coupling, is established utilizing the Lattice model and finite difference method. Thus, this project will provide a scientific basis for the safe operation of the deep strategic engineering structure.

向地下进军已成为人类未来拓展生存空间的必然，深部地下严酷环境极易造成混凝土的损伤劣化和结构性能退化。本项目针对深部工程结构服役环境“高应力、高温、高渗透压”的三大突出特征，运用热力学与多孔介质力学理论和现代测试技术，表征超高性能混凝土材料宏、细、微观结构特征及缺陷演变参数，揭示侵蚀离子运移、富集、吸附、固化及水分流动机理，发展深部应力场-温度场-渗流场耦合的时空演化及分布规律。在此基础上，综合考虑损伤叠加及多离子交互效应，通过Lattice和有限差分法建立多场多离子协同作用下微观-细观-宏观相结合的传输数值模型。研究成果为深部重大战略工程结构的安全运营提供科学依据。

向地下进军已成为人类未来拓展生存空间的必然，深部地下严酷环境极易造成混凝土的损伤劣化和结构性能退化。本项目针对深部工程结构服役环境“高应力、高温、高渗透压”的三大突出特征，采用先进的无损超声探测法、X射线衍射、低场核磁共振技术等，探明了高应力、高温、高渗透压作用下超高性能混凝土(UHPC)微结构演变机理，量化了UHPC多尺度结构缺陷的演变参数。基于CEMHYD3D水化微结构模型构建了拉荷载作用下的损伤数值模型，揭示了荷载作用下的损伤演变规律，实现了孔隙萌生-拓展-贯通过程的表征。揭示了高温作用下UHPC的热力响应，探明了高温作用下UHPC浆体湿热传递性能，确定了温度对湿度传递的加速程度。分析了渗透压作用对UHPC微结构损伤劣化规律，量化了渗透压力对水分传输的加速作用关系，揭示了渗透压下UHPC的渗流损伤耦合机制。发展了深部应力场-温度场-渗流场三场耦合的试验方法，追踪了侵蚀介质传输的时空规律。在此基础上，综合考虑损伤叠加及多离子交互效应，通过分子动力学、Lattice和有限差分法等建立了混凝土多场多离子协同作用下纳观-微观-细观-宏观相结合的传输数值模型。研究成果为深部重大战略工程结构的安全运营提供科学依据。