盐岩非平衡热力学本构模型及储库长期演化机理研究

The underground energy storage in salt rock is of great strategic significance for ensuring the national energy safety and economic development. Due to the complex geological conditions in our country, the construction of underground energy storage cavern in salt rock encounters great challenge and the long-term safety issue of storage cavern in salt rock needs to be solved urgently. In this research, the mechanism of instability and failure during the long-term evolution process of storage cavern in salt rock is focused on. The internal relationship between the mechanism of instability and failure and the time-dependent deformation and damage evolution of storage cavern in salt rock is investigated based on the non-equilibrium evolution in thermodynamics. The theoretical analysis, physical experiment and numerical simulation are used in this research. On the level of material, the thermodynamic creep damage constitutive model of salt rock is developed. The thermodynamic coupling mechanism of visco-elasticity, visco-plasticity and visco-damage of salt rock is investigated. The mechanical response and failure behaviors of salt rock under different loading conditions is investigated. On the level of structure, the theory of non-equilibrium evolution stability and control is developed. The internal effective driving force mechanism and evolution law of non-equilibrium evolution in rock mass under the external disturbance factors are investigated. The indicator and controlling method of long-term stability evaluation of rock mass. The constitutive model is calibrated and validated by a series of physical experiments. The finite element numerical method and simulation analysis platform are developed and applied to the long-term stability analysis of storage cavern in salt rock. The research work can provide scientific evidence for the long-term safety evaluation, prediction and quantitative control of storage cavern in salt rock.

盐岩地下能源储备对于保障我国能源安全和经济发展具有重大战略性意义。由于我国地质条件复杂，盐岩地下能源储库建设遇到了极大挑战，亟需解决盐岩储库的长期安全性问题。本项目针对我国盐岩储库长期演化过程中的失稳破坏机理，基于热力学非平衡演化思想来研究盐岩储库的时效变形，损伤演化与失稳破坏机理的内在联系。项目结合理论分析、物理实验和数值模拟，在材料层次上，建立盐岩热力学蠕变损伤本构模型，研究盐岩粘弹性-粘塑性-粘性损伤的热力学耦合机制，研究盐岩在各种加载状态下的力学响应和破坏行为；在结构层次上，建立非平衡演化稳定与控制理论，研究岩体结构在外部因素扰动下非平衡演化的内在有效驱动力机制和演化规律，建立岩体结构长期稳定评价指标及控制方法。通过一系列物理实验对本构模型进行参数标定和验证，建立有限元数值方法和仿真分析平台，应用于盐岩储库长期稳定分析，为盐岩储库的长期安全性评价和预测及其定量调控提供科学依据。

盐岩地下能源储备对于保障我国能源安全和经济发展具有重大战略性意义。由于我国地质条件复杂，盐岩地下能源储库建设遇到了极大挑战，亟需解决盐岩储库的长期安全性问题。在材料层次上，通过非平衡不可逆热力学理论和连续介质损伤力学理论分析和推导，基于有效应力原理和应变等效假设，将盐岩粘弹性，粘塑性和粘性损伤进行耦合，建立了盐岩热力学蠕变损伤本构模型方程；通过材料物理实验，研究了盐岩在恒定应力加载、加卸载、应变加载下的力学响应和破坏行为，对本构模型方程进行了参数标定和对比验证。在结构层次上，建立了非平衡演化稳定评价与控制理论的数学模型，超屈服力是盐岩结构体在外部因素扰动下非平衡演化的内在有效驱动力，塑性余能时间曲线反映了盐岩结构体非平衡演化规律，为盐岩结构体长期稳定提供了评价指标和控制方法。在有限元理论框架下，研究了盐岩蠕变损伤本构模型及非平衡演化稳定评价与控制理论数学模型的数值算法和程序实现。基于Abaqus软件用户材料子程序UMAT，对所建立的粘弹性、粘塑性和粘性损伤本构模型进行了数值方法实现，建立了大规模并行数值仿真计算平台。该计算平台已成功应用于地下能源储库的长期时效变形和破坏分析，大型地下隧洞围岩和支护系统的动态稳定和安全分析，煤层开采地层时效变形分析，高边坡长期稳定分析，煤矿坚硬顶板水力压裂等各个研究领域。该仿真计算平台具有很好的应用前景。