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.

灾难性的失败是脆弱的地球上的一种至关重要的现象，从人类引起的地震性到自然滑坡，火山喷发和地震。它始终与损坏的结构浓度相关，形式为较小的断层和裂缝的局部变形区域，最终导致沿着明显且新兴的断层平面沿系统大小的脆性故障。但是，局部定位过程尚不清楚 - 较小的裂缝通常会在失败之前立即自发自组织，但涉及的确切机制尚未确定。仍然存在许多问题，包括：Q1-裂纹，毛孔和晶界如何与施加的应力场在本地相互作用，以导致在特定位置，方向和时间发生灾难性失败？ Q2是什么决定了准静态和动态过程的相对重要性？和Q3-为什么只在某些情况下才能检测到灾难性失败的前体？在这里，我们将使用新开发的X射线透明变形单元格和快速同步X射线微型摄影来直接通过对整个定位过程进行成像来解决这些问题。我们将首次在同步加速器的高分辨率上首次在结构和地震上一起在结构和地震上的定位过程的性质和演变。我们将故意使用快速的电子监控和反馈控制来降低其进化的过程，并研究基本机制的应变率依赖性。这将提供对相关机制的前所未有的直接观察，包括地震（局部破裂产生声学排放）和无性抗压（弹性负荷和无声的不可逆损害）过程的贡献。这种创新的技术组合是及时，可行的，很可能会改变我们对微观过程在控制系统大小失败中的作用的理解。该结果将为自然和人类引起的地震性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。