Fracture process in rocks and earthquakes

由于岩石的脆性，岩石在所有长度尺度上都会破裂：从尺寸小于一毫米的颗粒(或晶界)中的微裂缝，到沿断层的巨大地震破裂，这些断层定义了数百公里长的构造边界。裂隙和破裂过程在确定岩石的本构响应和与灾难性岩石断层相关的地质灾害特征方面起着重要作用。因此，对岩石裂隙的调查将有助于我们了解和减轻地质灾害(地震、滑坡等)，解决矿山的安全问题(例如，斜坡失稳、岩爆)，并改善地下水和放射性废物的管理。从历史上看，了解岩石裂缝的研究工作主要集中在实验室静态裂缝以及地震观测和地震的数值模拟上。为了了解岩石在灾难性破坏中的动力学特性，有必要进行专门设计的实验。继申请人早先在实验室地震实验和自发破裂实验中的工作之后，他将研究地震断层在二维和三维方面的特征。申请者还将系统地测量岩石的动态断裂韧性和岩石的动态拉伸强度，这是岩石动态破坏量化的两个重要参数。这项研究将使用多伦多大学的岩石动态破裂设备(CFI-Young Lead PI)、高速相机和气枪合作进行。此外，申请者正在使用多伦多大学的初创企业奖制造气枪，并正在准备CFI/LOF申请超高速相机的提案。

Due to its brittle nature, rock breaks at all length scales: from micro-cracks in grains (or along grain boundaries) with sizes smaller than a millimeter to huge earthquake ruptures along faults that define tectonic boundaries with lengths of hundreds of kilometers. Fractures and fracture processes play an important role in the determination of the constitutive response of rocks and the characteristics of geological hazards that are associated with catastrophic rock faults. Thus, the investigation of fractures in rocks will help us understand and mitigate geological hazards (seismic, landslide, etc.), address safety issues in mines (e.g., slope instability, rockbursts), and improve the management of groundwater and radioactive waste. Historically, research efforts to understand rock fractures have been focused mainly on laboratory static fractures and on the seismic observations and numerical simulations of earthquakes. In order to understand the dynamic properties of rocks involved in catastrophic failures, specially designed experiments are necessary. Following the applicant's earlier work in the laboratory earthquake experiments and spontaneous fracture experiments, he will study the characteristics of earthquake faulting in both two- and three-dimensions. The applicant will also systematically measure the dynamic fracture toughness of rocks and the dynamic tensile strength of rocks, two important parameters in the quantification of dynamic rock failure. The research will be carried out using the Rock Dynamic Fracture Facility (CFI-Young lead PI) at the University of Toronto, the high speed camera, and the gas gun through collaboration. In addition, the applicant is building a gas gun using the start-up award from the University of Toronto and is preparing a CFI/LOF proposal to request an ultra high speed camera.