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

MEMIN计划框架内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。调查包括（i）确定冲击载荷前后目标岩石的强度特性，以推断撞击成坑后强度降低的程度。冲击波和压力波对多孔岩石的压缩导致岩石组构的实质性变化。我们将调查（二）不同的模式，包括本地化的孔collpase，可能会导致形成的压实带的径向距离的函数在地板上的实验室产生的撞击坑的压实。并将其结果与准静态加载试验中形成的致密脆性变形特征进行了比较。(iii)冲击变形岩石的损伤状态将通过测定微裂纹和缺陷的密度来量化。这些数据将与项目4中获得的超声波测量反演获得的弹性参数相关。(iv)最后，我们打算测试和校准一种新型的天然压力计，即冲击变形砂岩中Dauphiné双晶的形成，并应用新型同步加速器微焦点劳厄衍射技术确定岩石的残余应力。

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.