Deformation Mechanics of an Asperity under Hydrothermal Conditions

水热条件下凹凸体的变形力学

• 批准号: 0609617
• 负责人: Brian Evans
• 金额: $ 42.3万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-11-01 至 2010-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0609617&HistoricalAwards=false
• 关键词: Deformation; Mechanics; Asperity; under; Hydrothermal

Pressure solution is a deformation mechanism involving fluid-laden granular rocks at relatively shallow depths in the continental crust. Such solution transport mechanisms are important during natural processes, including the compaction of sediments, subsidence of sedimentary basins, fault strengthening, and crustal orogeny, and for engineering and industrial applications, such as the characterization of aquifers, transport of pollutants, oil exploration and production, geothermal energy recovery, nuclear waste disposal, and carbon dioxide sequestration. Although there is copious evidence of the importance of this ubiquitous process, a detailed constitutive law does not exist that would enable scientists to predict the rate of deformation under the natural conditions. In this project, both numerical experiments and laboratory tests are being conducted to investigate the physics and kinetics of deformation at small asperities in granular materials. The experiments are being done by students and staff at the Massachusetts Institute of Technology, in collaboration with S. Hickman and N. Beeler, USGS, Menlo Park. The experiments are designed to measure deformation of quartz asperities pressed against either quartz or sapphire plates at temperatures up to 600 C and fluid pressures of 150 MPa or less for periods of 1-4 weeks. For the initial lab experiments, sapphire is being used as a proxy "insoluble" mineral because it is easily polished, strong, and transparent enough to be used as a window material. The microstructure produced at the contact region is being observed after deformation using optical, transmission electron, and scanning electron microscopy. In addition to the laboratory experiments, numerical calculations are being performed to investigate the coupling of transport, dissolution, and precipitation processes, the effect of variations in stress distribution, the production or decay of transients, and the relation of the kinetics of the asperity deformation to the kinetics of the component processes. Initial numerical models suggest a much more intricate coupling of the processes than thought heretofore. In addition, the calculations predict a rather long transient period that will, if confirmed, be critical to understand if laboratory experiments are to be extrapolated accurately to natural conditions.

压力溶液是一种变形机制，涉及大陆壳中相对较浅的深度处含有液体的颗粒岩石。这种解决方案的传输机制在自然过程中很重要，包括沉积物的压实，沉积盆地的沉降，断层加强和地壳造口症以及用于工程和工业应用，例如含水层的表征，污染物的运输，石油勘探和生产，生产，地热能量，核废料恢复，核浪费和碳二氧化碳纤维二氧化物。尽管有大量的证据表明这种无处不在的过程的重要性，但不存在详细的构造法，这将使科学家能够预测自然条件下的变形率。在该项目中，正在进行数值实验和实验室测试，以研究颗粒材料中小小的不稳定的变形的物理和动力学。这些实验是由马萨诸塞州理工学院的学生和员工与S. Hickman和N. Beeler，Menlo Park的S. Hickman和N. Beeler合作进行的。该实验旨在测量在高达600 c的温度下针对石英或蓝宝石板压力的石英覆盖率的变形，并在1-4周内降低了150 MPa或更少的流体压力。对于最初的实验室实验，蓝宝石被用作代理“不溶”矿物，因为它易于抛光，牢固且透明，足以用作窗户材料。使用光学，透射电子和扫描电子显微镜在变形后观察到在接触区域产生的显微结构。除了实验室实验外，还进行了数值计算，以研究运输，溶解和降水过程的耦合，应力分布变化的影响，瞬态的产生或衰减以及呈阳离子变形的动力学与组件过程的动力学的关系。最初的数值模型表明，该过程的耦合比迄今为止的耦合要复杂得多。此外，计算预测的是一个相当长的瞬时周期，如果确认，对于了解实验室实验是否准确地外推到自然条件至关重要。