Compaction, strength reduction, and stress estimates in shocked porous sandstones

冲击多孔砂岩中的压实、强度折减和应力估计

• 批准号: 111492746
• 负责人: Professor Dr. Georg Dresen
• 金额: --
• 依托单位: Department of Earth and Planetary Science
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/111492746?language=en
• 关键词: Compaction; strength; reduction; stress; estimates

The proposed project in the framework of the MEMIN program is devoted to better understand deformation processes and structural changes in porous sandstones in impact craters. The investigations comprise (i) the determination of strength properties of target rocks prior and after shock loading to infer the degree of strength reduction upon impact cratering. The compression of porous rocks by shock and pressure waves leads to substantial changes in the rock fabric. We will investigate (ii) different modes of compaction including the localized pore collpase that could lead to the formation of compaction bands as a function of radial distance in the floor of laboratory produced impact craters. The results will be compared with compactive britte deformation features formed in quasi-static loading tests. (iii) The state of damaging of impact-deformed rocks will be quantified by determination of the densities of microcracks and defects. These data will be related to elastic parameters that are gained from inversion of ultrasonic measurements obtained in Project 4. (iv) Finally, we intend to test and calibrate a novel natural pressure gauge, namely the formation of Dauphiné twins, in shock deformed sandstones and determine the residual stresses of the rocks applying the novel synchrotron microfocus Laue diffraction technique.

MEMIN计划框架下的拟议项目致力于更好地了解撞击坑中多孔砂岩的变形过程和结构变化。研究包括(i)确定目标岩石在冲击载荷之前和之后的强度特性，以推断撞击后强度降低的程度。冲击波和压力波对多孔岩石的压缩导致岩石结构发生实质性变化。我们将研究（ii）不同的压实模式，包括局部孔隙坍塌，它可能导致压实带的形成，作为实验室产生的陨石坑底部径向距离的函数。结果将与准静态加载试验中形成的压实脆性变形特征进行比较。（三）通过测定微裂纹和缺陷的密度来量化冲击变形岩石的破坏状态。这些数据将与从项目4中获得的超声波测量反演中获得的弹性参数有关。（iv）最后，我们打算在冲击变形砂岩中测试和校准一种新的自然压力计，即dauphin<s:1>孪生体的形成，并应用新型同步加速器微聚焦劳厄衍射技术确定岩石的残余应力。