Collaborative Research: Further Investigation of the Onset and Evolution of Compaction and Dilation Bands

摘要本项目是对压实和膨胀带形成的实验和理论研究的延续，探讨了关于局部带形成条件的几个关键问题。具体项目活动包括：1)应力集中对压实带形成/演化的影响研究；2)层理和各向异性对压实带形成的影响研究；3)阿兹特克砂岩局部化特征研究及与近期现场发现的对比研究；5)建立和评价基于双损伤机制的本构模型，以表征观察到的细观损伤机制。实验工作，连同已发表的数据，提供了一套完整的多孔砂岩力学和微观结构数据。进一步的理论分析考察了本构模型和应力状态对局部化条件的影响，并纳入了实验推导的材料参数约束。通过综合实验和理论结果，推导了一个模型，用于预测不同应力状态和加载路径下地壳环境下的破坏模式和局部化发展。

AbstractThis project, a continuation of experimental and theoretical investigation of compaction and dilation band formation, examines several critical questions regarding conditions for localized band formation. Specific project activities include: 1) investigation of the influence of stress concentration on compaction band initiation/evolution, 2) investigation of the influence of bedding and anisotropy on compaction band formation, 3) examination of the localization behavior in Aztec sandstone and comparison with recent field findings, 4) investigation of dilation band formation in porous sandstone under triaxial extension, and 5) development and evaluation of two-damage mechanism based constitutive models to represent observed microstructural damage mechanisms. The experimental work, together with published data, provides a compete set of mechanical and microstructural data on porous sandstones. Further theoretical analyses examine the influence of constitutive models and stress state on localization conditions, and include incorporation of experimentally derived material parameter constraints. By synthesizing experimental and theoretical results, a model is extrapolated to predict failure modes and localization development in crustal settings for different stress states and loading paths.