层状盐穴储气库盐泥互层体的分数阶损伤力学模型研究

The rock salt formation in China is the lacustrine deposits rich in muddy intercalations. Multiple interlayers and thin single layer are typical characteristics of the bedded rock salt. The interlayers and interlaminations of rock salt and mudstone interbedding are the weak locations that cause damage and form seepage channels, which is one of the general basic problems that the strategic layered rock salt storage cavern construction is facing in China, thus the damage mechanical model of rock salt and mudstone interbedding is in need of in-depth research. Aiming at the unique rock salt and mudstone interbedding of layered rock salt in China, based on the structural analysis, macroscopic and microscopic mechanical testing, through the comprehensive use of the monomer deformation monitoring, acoustic emission monitoring, CT scan reconstruction and the localized stress and deformation field reconstruction, this project is proposing to discuss the localized deformation effect and damage evolution properties of rock salt and mudstone interbedding with the effect of different interlayers,and reveal the meso damage mechanism of the destruction of rock salt and mudstone interbedding. Comprehensively using mechanics, graphics, and statistics to discuss the use of the interlayer impact factor to uniformly describe the relationship between the interlayers with different properties and the mechanical behaviour of rock salt and mudstone interbedding, explore the definition of damage variable with the interlayer effect and establish damage evolution equation based on image reconstruction. Therefore the fractional damage mechanical model which is fused with interlayer influence and damage variables can be initially established,which is able to provide theoretical basis not only for the research of bedded salt carven construction, but also for the study of damage mechanism of interbedded rock mass.

中国盐岩地层是富含泥质夹层的湖相沉积，夹层多和单层厚度薄是其典型特征。盐泥互层体的夹层及层间是导致损伤和形成渗漏通道的薄弱部位，是中国层状盐穴能源战略储库建设面临的共性基础问题之一，亟待对盐泥互层体的损伤力学模型开展深入研究。本项目针对中国层状盐岩独特的盐泥互层体，拟通过组构分析、宏细观力学试验，综合采用单体变形监测、声发射监测、CT扫描重构及应力与变形局部化效应场重建等技术，探讨不同互层性状夹层影响的互层体变形与损伤演化特征，揭示夹层影响下盐泥互层体变形破坏的细观损伤机理；综合运用力学、图像学及统计学，探讨用夹层影响因子统一描述不同性状夹层与互层体力学行为的相关关系，探索应用重构图像定义具有互层影响效应的损伤变量及建立损伤演化方程，初步建立耦合夹层影响因子和损伤变量的分数阶损伤力学模型。研究成果不仅可为层状盐穴储气库建设研究提供理论基础，还可为其他互层岩体损伤机理研究提供借鉴。

本项目针对我国层状盐穴储气库中夹层多的共性基础问题，开展了盐岩与泥岩互层体变形破坏过程细观损伤机理与分数阶损伤力学模型研究。以层状盐穴中典型的泥岩夹层和互层类型为对象，从物质属性入手，开展了系列物质组分与细观结构分析，并通过互层体蠕变破坏与AE三维监测、CT扫描及互层单体变形等测试，重构了损伤图像，分析了互层体变形及损伤演化特征，对表征夹层效应的影响因子及损伤变量与计算方法进行了研究，建立了分数阶损伤力学模型，并以河南平顶山为地质条件为背景，开展了储库优化仿真分析。发表论文25篇，获得发明专利授权15项，毕业研究生7人、本科生2人。