Collaborative Research: Use of Novel True Triaxial Tests and Shear Band Theory to Determine Failure Properties of Compactive Porous Sandstones

合作研究：利用新型真三轴试验和剪切带理论确定压实多孔砂岩的破坏特性

• 批准号: 0940981
• 负责人: John Rudnicki
• 金额: $ 6.36万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-15 至 2014-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0940981&HistoricalAwards=false
• 关键词: Collaborative; Research; Use; Novel; True

A research team from the University of Wisconsin-Madison and Northwestern University is combining experimental observations and shear band analysis in order to investigate the failure properties of high porosity rock. Shear band analysis is a mathematical description of the observed behavior of materials such as rocks by which their failure under applied stresses is concentrated in a narrow band rather than being uniformly distributed. True triaxial tests, in which test samples are subjected to three independent and typically unequal principal stresses simulating realistic field conditions, are being conducted on high-porosity compactive sandstones. The tests employ novel loading paths for each of the principal stresses. These paths, unprecedented in laboratory experiments, are designed to facilitate formulation of constitutive relations and comparison with the theoretical predictions of shear band analysis. The results of this research will provide the first systematic test of the applicability of shear band theory for the full range of stress conditions.A better understanding of rock mechanical behavior and its relation to failure of compactive porous sandstones is essential for interpreting field observations and as input for numerical simulations of complex geomechanical and geophysical problems. These include earthquake mechanics, design of underground storage facilities, energy recovery and sequestration of carbon dioxide. Failure in these materials tends to occur in narrow bands and therefore can drastically alter the ability of the rock formation to trap or transmit fluids. These narrow zones of failure may reduce flow across them and interfere with fluid circulation in applications involving fluid injection (e.g. for carbon dioxide sequestration or liquid waste isolation) and fluid extraction (e.g. for oil field operations). These failure zones can also provide conduits for enhanced flow along them. Such flow can disrupt rock formations intended to trap fluids and prevent them from reaching the surface or interacting with shallow groundwater.

来自威斯康星大学麦迪逊分校和西北大学的一个研究小组正在将实验观察和剪切带分析相结合，以研究高孔隙率岩石的破坏特性。剪切带分析是对岩石等材料观察到的行为的数学描述，通过这种分析，它们在施加应力下的破坏集中在窄带内，而不是均匀分布。真正的三轴试验是在高孔隙率致密砂岩上进行的，其中测试样品承受三个独立且通常不相等的主应力，模拟实际现场条件。该测试对每个主应力采用新颖的加载路径。这些路径在实验室实验中是前所未有的，旨在促进本构关系的制定以及与剪切带分析的理论预测的比较。这项研究的结果将为剪切带理论在各种应力​​条件下的适用性提供首次系统测试。更好地了解岩石力学行为及其与致密多孔砂岩破坏的关系对于解释现场观测结果和分析至关重要。复杂地质力学和地球物理问题数值模拟的输入。其中包括地震力学、地下储存设施的设计、能量回收和二氧化碳封存。这些材料的破坏往往发生在窄带中，因此会极大地改变岩层捕获或传输流体的能力。这些狭窄的失效区域可能会减少穿过它们的流量，并干扰涉及流体注入（例如用于二氧化碳封存或液体废物隔离）和流体提取（例如用于油田作业）的应用中的流体循环。这些破坏区域还可以提供管道以增强沿它们的流动。这种流动会破坏旨在捕获流体的岩层，并阻止它们到达地表或与浅层地下水相互作用。