Collaborative Research: Development of a Fracture Processes Facility at DUSEL Homestake

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。拟议的研究是针对NSF的主要研究设备和设施建设（MREFC）项目的初步设计报告的准备：深地下科学和工程实验室（DUSEL）在前霍姆斯特克在南达科他州的矿井。智力优势：该奖项将使用热技术在1-100米的尺度上创建精心控制的断层，以修改原地应力，使岩石在剪切中失效。这些实验将扩展实验断层成核和增长的长度尺度2-3个数量级以上，目前在实验室中可能。实验将在修改后的原地应力足以驱动断层的深度进行，从而避免了对大型昂贵的加载框架的需要。DUSEL Homestake提供了一个机会，通过提供进入垂直应力高达60 MPa（下至2400米深）的位置，足以产生故障，进行一个独特的实验计划。它还允许在不同深度的设施，允许在不同的压力水平下进行实验。这些拟议的实验需要一个设施，在受控的环境中提供进入深层地下的大量岩石，并鼓励跨学科合作;所有条件都在DUSEL Homestake得到满足。这项研究的最终科学目标是大大提高对结晶岩断层过程的理解，特别强调断层是如何通过完整的岩石启动和生长的。另一个重要的目标是观察和表征一个自然的，现有的故障的复活。两者都可以在Homestake中完成。我们提出的实验套件是出于地球科学的基本需求，以促进对岩石如何因断裂而失败的理解。该实验特别响应于Deep Science中的想法，以及DUSEL S1技术报告中的指导和实验，并由EarthLab的诱导断裂和变形过程实验室推动。更广泛的影响：岩石力学领域以外的其他实验将受益于，并可以伴随，拟议的实验。实验将解决在以前完整的岩石剪切裂缝的形成，滑动预先存在的关节，断层泥的形成，断层泥对断层复活的影响，以及断层渗透性的演变。它将进一步了解水力压裂，断裂能和岩石强度如何随尺寸而变化，以及微生物系统如何利用裂缝。研究结果将直接应用于地热能和碳氢化合物的生产，以及地下废物的储存和环境修复。由于这项研究具有高度跨学科性，它将为现有和子孙后代的科学家和工程师提供丰富的环境来培养新的想法。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The proposed research is directed towards the preparation of a Preliminary Design Report for an NSF Major Research Equipment and Facility Construction (MREFC) project: The Deep Underground Science and Engineering Laboratory (DUSEL) at the former Homestake mine in South Dakota. Intellectual Merit: This award will create carefully controlled faults at scales of 1-100 meters using thermal techniques to modify in situ stresses to the point where the rock fails in shear. These experiments will extend experiments on fault nucleation and growth to length scales 2-3 orders of magnitude greater than are currently possible in the laboratory. The experiments would be done at depths where the modified in situ stresses are sufficient to drive faulting, obviating the need for large, expensive loading frames. DUSEL Homestake presents an opportunity to conduct a unique experimental program by providing access to locations with vertical stresses as large as 60 MPa (down to 2400 meter depth), more than sufficient to create faults. It also allows facilities at different depths, permitting experiments to be conducted under different stress levels. These proposed experiments require a facility providing access to large rock volumes in the deep subsurface in a controlled setting, and one where interdisciplinary collaborations are encouraged; all the conditions are met at DUSEL Homestake. The ultimate scientific objective of this research is to substantially elevate understanding of faulting processes in crystalline rock, with particular emphasis on how faults are initiated and grow through intact rock. Another important objective is to observe and characterize the reactivation of a natural, existing fault. Both can be done at Homestake. The experimental suite we propose is motivated by a fundamental need across geosciences to advance the understanding of how rocks fail by fracturing. The experiment responds specifically to ideas in Deep Science, and to guidance and experiments in the DUSEL S1 Technical Report, and it is motivated by the Induced Fracture and Deformation Processes Laboratory in EarthLab. Broader Impacts: Other experiments outside the field of rock mechanics will benefit from, and can accompany, the proposed experiments. The experiments will address formation of shear fractures in previously intact rock, slip on pre-existing joints, fault gouge formation, the influence of fault gouge on fault reactivation, and the evolution of fault permeability. It will further understanding of hydraulic fracturing, how fracture energy and rock strength scale with size, and how microbial systems exploit fractures. The results of the research will have direct applications for the production of geothermal energy and hydrocarbons, as well as the storage of waste and environmental remediation in the subsurface. Since the research is so highly cross-disciplinary, it will provide a rich environment for fostering new ideas among existing and future generations of scientists and engineers.