Triaxial data, hydrostatic loading data and processed representative elementary area (REA), grain size image analysis data for Bentheim, Castlegate and a synthetic sandstone sample (NERC Grant NE/L002469/1)

We examine the role of cement on compaction band formation by performing triaxial tests on three sandstones, Bentheim, Castlegate and a synthetic sandstone which possess very similar porosities (~26-29%) and grain sizes (~230-300 µm), but which are cemented differently, with syntaxial quartz overgrowths, clay, and amorphous quartz cement respectively. Each sample was taken to 5% axial strain at a starting effective stress equivalent to 85% of its hydrostatic yield (P*) value, which were identified from yield under hydrostatic loading. These data for the 3 samples are presented as matlab data files. Post-deformation, each of the 3 cores underwent backscatter SEM and subsequent image analysis to examine any localised variations in porosity and grain size. These data are presented as csv files. Discrete bands form in each of the 3 sandstones but are distributed differently across each sample. Our results suggest that cement type plays a significant role in the micromechanics of deformation within each of the sandstones, which in turn, determines where the compaction bands nucleate and develop. These results may provide a starting point to investigate the role of cement on compaction localisation further.

本研究旨在探讨水泥在压实带形成过程中的作用，通过对三种具有相似孔隙率（约26-29%）和粒径（约230-300微米）的砂岩（Bentheim、Castlegate以及一种合成砂岩）进行三轴试验，并分别以同质石英生长、粘土和玻璃态石英水泥进行不同方式固结，以分析水泥类型对压实带形成的影响。每个样本在起始有效应力相当于其静水屈服值（P*）的85%时，被拉伸至5%的轴向应变，此屈服值由静水加载下的屈服确定。这些数据以MATLAB数据文件的形式呈现。变形后，每个岩心均经过背散射扫描电子显微镜（SEM）和后续图像分析，以检查孔隙率和粒径的局部变化。这些数据以CSV文件的形式展示。在三种砂岩中均形成了离散的压实带，但其在每个样本中的分布各不相同。我们的研究结果表明，水泥类型在砂岩变形的微观力学中起着重要作用，进而决定了压实带的成核和发育位置。这些结果可能为深入研究水泥对压实带局部化的作用提供初步线索。