U.S.-Switzerland Cooperative Research on the Physics and Mechanics of Dehydration Embrittlement in Gypsum

此奖项支持黄腾方教授及一位 学生和博士后合作， 心理和理论物理学研究与教授 美国地质研究所的肯尼斯·许和大卫·奥尔加德说， 瑞士苏黎世联邦理工学院。 这些调查员都对 在基础物理学和机械学的过程中， 石膏脱水脆化。 他们建议执行一个 系统研究了脱水速率、渗透率和 在控制条件下石膏的孔隙度变化 温度、孔隙压力、应力和应变率。 他们将 定量表征分解的演化 用X射线和电子显微镜观察反应和孔结构 技术. 并从理论上分析了 在脱水反应、孔隙度和渗透率之间。 最终，这项实验和理论工作将使 以数字计算弱化和脆化的程度， 在诸如汝拉山的逆掩构造的底部， 山在瑞士 这种模拟的结果将 与实际地质观测结果进行比较， 领域 合作者带来了互补的专业知识， 这是指导劳动分工的工作。 的 高温、高压变形实验及 X射线分析将在ETH进行。 微结构 将在ETH和纽约州立大学斯托尼布鲁克分校进行观察。 的 渗透率测量和理论分析将是 在斯托尼布鲁克演出。 从现场和实验室观察中已经认识到 岩石的变形变质作用与 有联系 然而，大部分工作都是在低孔隙度下进行的 结晶岩石的非弹性和破坏行为 与温度、压力和应变速率敏感相关。 这些因素不足以解释多孔介质的行为。 岩石，如石膏，或经历过变质作用的岩石。 含水相的分解或压实 在逆冲变质作用期间，可能导致脆化， 弱化 在行为上还有进一步的差异， 多孔岩石脱水。 拟议的研究将调查 这些变化在“排水”和“不排水”的配置， 石膏。 这些结果将大大有助于理解 沉积岩层的构造学。

This award supports Professor Teng-fong Wong and a graduate student and post-doctoral associate to collaborate in experi- mental and theoretical geophysics research with Professors Kenneth Hsu and David Olgaard of the Geological Institute of the ETH, Zurich, Switzerland. These investigators share an interest in the fundamental physics and mechanics of the process of dehydration embrittlement in gypsum. They propose to perform a systematic study of the dehydration rate, permeability and porosity change in gypsum under controlled conditions of temperature, pore pressure, stress and strain rate. They will quantitatively characterize the evolution of the decomposition reaction and pore structure using x-ray and electron microscopy techniques. Also, they will analyze theoretically the relation among the dehydration reaction, the porosity and the permeability. Ultimately, this experimental and theoretical work will enable them to compute numerically the degree of weakening and embrittle- ment at the bottom of an overthrust formation such as the Jura mountains in Switzerland. The results of such modelling will of course be compared with actual geological observations in the field. The collaborators bring complementary expertise and facilities to this work that guide the division of labor. The high temperature, high pressure deformation experiments and the x-ray analysis will be conducted at ETH. The microstructural observations will be done at ETH and SUNY at Stony Brook. The permeability measurements and theoretical analysis will be performed at Stony Brook. It has been recognized from field and laboratory observations that the deformation and metamorphism of rocks are closely linked. However, most of this work has been done on low porosity crystalline rocks for which the inelasticity and failure behavior are sensitively linked to temperature, pressure and strain rate. These factors are insufficient to explain the behavior of porous rocks, such as gypsum, or rocks that have undergone metamorphism. The decomposition or compaction of water-bearing (hydrous) phases during prograde metamorphism may lead to embrittlement and weakening. There are further differences in behavior as the porous rock is dehydrated. The proposed research will investigate these changes in both "drained" and "undrained" configurations of gypsum. The results will contribute substantially to understanding the tectonics of sedimentary rock formations.