We present new true triaxial compression data obtained in the ductile regime on Bleurswiller sandstone. The deformed samples show a range of failure modes qualitatively similar to what was reported by earlier experimental studies performed in conventional conditions (axisymmetric compression). In particular, visual inspection and X-ray Computed Tomography imaging reveal compaction localization in all our deformed samples. The pore collapse model of Zhu et al.( 2010) 1 is extended to include the role of the intermediate principal stress and our new data for the onset of shear-enhanced compaction are in basic agreement with this extended model that includes three stress invariants. Published true triaxial data obtained in the brittle regime highlights the impact of the intermediate principal stress on the onset of dilatancy. The predictions of the conventional sliding wing crack model extended to true triaxial conditions are in poor agreement with these data. Another energetic approach pioneered by Wiebols & Cook shows a better agreement with the experimental results. Our new data and analysis will help the interpretation of inelastic deformation under polyaxial compression in various geotechnical and tectonic settings.

中文翻译：

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真三轴压缩下多孔砂岩孔隙塌陷的发生和膨胀性：实验观察和微观力学建模


我们提出了在 Bleurswiller 砂岩的延展性状态下获得的新真实三轴压缩数据。变形样本显示出一系列失效模式，与早期在常规条件下进行的实验研究（轴对称压缩）所报告的失效模式在质量上相似。特别是，目视检查和 X 射线计算机断层扫描成像揭示了我们所有变形样品的压实定位。Zhu et al.（ 2010） 1 的孔隙塌陷模型被扩展为包括中间主应力的作用，我们关于剪切增强压实开始的新数据与这个包含三个应力不变量的扩展模型基本一致。在脆性状态下获得的已发表的真实三轴数据强调了中间主应力对剪胀开始的影响。传统滑翼裂纹模型扩展到真实三轴条件的预测与这些数据的一致性很差。Wiebols&Cook开创的另一种充满活力的方法与实验结果显示出更好的一致性。我们的新数据和分析将有助于解释各种岩土工程和构造环境中多轴压缩下的非弹性变形。