基于热-水-力-化学耦合效应的裂隙岩石损伤断裂与止裂研究

This project is frontier research in the field of rock mechanics. It aims to solving the thermo-hydro-mechanical-chemical (THMC) coupling fracture of rock in deep rock mass engineering such as deep petroleum and mining exploitation, geothermal utilization, nuclear waste disposal and underground energy storage. Based on analyses of the thermo-hydro-mechanical-chemical (THMC) coupling mechanism, non-equilibrium thermodynamics, fluid mechanics, fracture mechanics and chemical kinetics, THMC coupling damage-fracture mechanics is established including damage constitutive model, crack propagation control equation, fracture criterion and cracking-arrest condition in order to analyze the whole THMC coupling process of rock deformation, damage(crack initiation), crack propagation control equation and final fracture. A new calculation program of THMC coupling damage constitutive model is made for user -redevelopment platform of finite element software to analyse THMC coupling stress and strain. Self-designed THMC coupling fracture and cracking-arrest test of rock and scanning electron microscopy test of fractured surface are used to study the influences of multi-physical field parameters on the THMC coupling crack propagation rate,fracture modes (tension, shear, minxed mode fracture) and crack-arrest effect and reveal the THMC coupling fracture and cracking-arrest mechanism. This study is of great significance only for the development of rock fracture mechanics but also for the strength calcuation, safety assessment and cracking-arrest design in deep rock mass engineering.

本项目瞄准国际岩石力学领域研究前沿，针对我国深部矿产和石油开采、地热开发、核废料处置、地下能源储存等工程中迫切需要解决的裂隙岩石热-水-力-化学（THMC）耦合断裂问题开展系统深入研究。基于THMC耦合作用机理分析，在非平衡态热力学、流体力学、断裂力学、化学动力学等相结合的理论框架下，建立裂隙岩石THMC耦合损伤断裂与止裂理论（含损伤本构模型、裂纹扩展控制方程、断裂准则、止裂条件），阐明THMC耦合断裂全过程演变规律，并编制有限元二次开发程序计算和分析THMC耦合应力场分布规律；通过自行设计THMC耦合断裂与止裂试验，研究多物理场参数对裂隙岩石THMC耦合裂纹扩展速度、断裂模式、止裂效应的影响规律，揭示THMC耦合断裂与止裂机理，提出THMC耦合裂纹止裂方法。本研究不仅对岩石断裂力学发展具有重要的理论意义，而且对THMC耦合作用下深部岩体的强度计算、安全评估、止裂设计等具有重要的应用价

本项目瞄准国际岩石力学领域研究前沿，针对深部矿产和石油开采、地热开发、核废料处置、地下能源储存等工程中亟待解决的裂隙岩石热-水-力-化学（THMC）耦合损伤断裂与止裂问题开展系统深入的研究。基于THMC耦合作用机理分析，首次建立了裂隙岩石THMC耦合损伤断裂与止裂理论（含损伤本构模型，裂纹起裂、扩展与断裂等准则，止裂条件），提出了基于PFC3D的细观参数定量分析方法和细观断裂准则；通过自行研制的THMC耦合断裂与止裂试验（含渗透率的实时检测、裂纹扩展速率的连续监测等新方法）、电镜实验和PFC3D数值模拟，研究了多物理场参数（温度、水压、围压、溶液PH值）对裂隙岩石THMC耦合裂纹起裂与扩展规律、断裂模式（拉伸、剪切、拉-剪复合型）和止裂效应的影响规律，揭示了裂隙岩石THMC耦合断裂与止裂的宏-细-微观机理，验证了新理论的合理性和有效性，并提出了脆性岩石THMC耦合裂纹扩展的止裂设计建议方法。研究成果不仅对岩石断裂力学发展具有重要的理论意义，而且对THMC耦合作用下深部岩体的强度计算、安全评估、止裂设计等提供重要的理论依据。