Catastrophic Failure: what controls precursory damage localisation in rocks?

灾难性破坏：什么控制着岩石中的先兆损伤定位？

基本信息

批准号：
NE/R001693/1
负责人：
Ian Main
金额：
$ 80.91万
依托单位：
University of Edinburgh
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FR001693%2F1
关键词：
Catastrophic Failure what controls precursory

项目摘要

Catastrophic failure is a critically-important phenomenon in the brittle Earth on a variety of scales, from human-induced seismicity to natural landslides, volcanic eruptions and earthquakes. It is invariably associated with the structural concentration of damage in the form of smaller faults and fractures on localised zones of deformation, eventually resulting in system-sized brittle failure along a distinct and emergent fault plane. However, the process of localisation is not well understood - smaller cracks spontaneously self-organise along the incipient fault plane, often immediately before failure, but the precise mechanisms involved have yet to be determined. Many questions remain, including : Q1 - How do cracks, pores and grain boundaries interact locally with the applied stress field to cause catastrophic failure to occur at a specific place, orientation and time?; Q2 what dictates the relative importance of quasi-static and dynamic processes?; and Q3 - why can we detect precursors to catastrophic failure only in some cases? Here we will address these questions directly by imaging the whole localisation process, using a newly-developed x-ray transparent deformation cell and fast synchrotron x-ray micro-tomography. We will visualise the nature and evolution of the localisation process structurally and seismically together for the first time at high resolution in a synchrotron. We will deliberately slow the process to image its evolution, and to investigate the strain-rate dependence of the underlying mechanisms, using rapid electronic monitoring and feedback control. This will provide unprecedented direct observation of the relevant mechanisms, including the contribution of seismic (local cracking producing acoustic emissions) and aseismic (elastic loading and silent irreversible damage) processes to the outcome. This innovative combination of techniques is timely, feasible, and is likely to transform our understanding of the role of microscopic processes in controlling system-size failure. The results will provide interpretive models for similar processes in natural and human-induced seismicity, including scale-model tests of strategies for managing the risk of large induced events.

从人为引发的地震活动到自然滑坡、火山爆发和地震，灾难性破坏是脆弱地球上一种极其重要的现象。它总是与局部变形区域上较小的断层和裂缝形式的结构损伤集中相关，最终导致沿明显且紧急的断层面发生系统规模的脆性破坏。然而，局部化的过程还没有被很好地理解——较小的裂纹通常在失效前立即沿着初始断层面自发地自组织，但所涉及的精确机制尚未确定。许多问题仍然存在，包括： Q1 - 裂纹、孔隙和晶界如何与所施加的应力场局部相互作用，从而导致在特定位置、方向和时间发生灾难性故障？ Q2 什么决定了准静态和动态过程的相对重要性？ Q3 - 为什么我们只能在某些情况下检测到灾难性故障的先兆？在这里，我们将使用新开发的 X 射线透明变形单元和快速同步加速器 X 射线显微断层扫描，通过对整个定位过程进行成像来直接解决这些问题。我们将首次在同步加速器中以高分辨率将定位过程的性质和演化从结构上和地震上可视化。我们将故意放慢这一过程，以对其演化进行成像，并使用快速电子监控和反馈控制来研究潜在机制的应变率依赖性。这将为相关机制提供前所未有的直接观察，包括地震（产生声发射的局部裂缝）和抗震（弹性载荷和无声不可逆损坏）过程对结果的贡献。这种创新的技术组合是及时、可行的，并且可能会改变我们对微观过程在控制系统规模故障中的作用的理解。研究结果将为自然和人为诱发的地震活动中的类似过程提供解释模型，包括管理大型诱发事件风险的策略的比例模型测试。