The mechanical properties of shales, a type of heterogeneous and multiphase composite, are of multiscale characteristics in nature. A large number of indentation measurements were performed under the continuous stiffness measurement (CSM) mode on the Longmaxi shale, followed by data segmentation, Gaussian mixture modeling (GMM) deconvolution of segmented datasets, and results re-integration. Accompanying compositional analyses by X-ray powder diffraction and surface imaging were also conducted to assist data interpretation. Results showed that the studied shale consisted of a fine-grained, relatively homogeneous clay matrix with randomly embedded, coarse-grained solid inclusions of up to ~ 100 μm in size. The CSM mode enabled the analysis of phase angle lag, which is an effective indicator for surface roughness. The Young’s moduli of both microscopic constituent phases (e.g., clay matrix, carbonates, quartz, pyrite) and macroscopic bulk shale were precisely determined and, through the probability analysis of the indent locations, the characteristic lengths of the shale’s constituent phases were estimated. The clay matrix and carbonates have relatively large characteristic lengths than quartz and pyrite. The data analytics proposed in this study may provide a feasible framework to assess the multiscale mechanical properties as well as the characteristic lengths of the shale’s constituent phases via a single type of measurement technique on the same piece of sample.

页岩是一种非均质多相复合材料，其力学性质具有多尺度特征。在龙马溪页岩连续刚度测量（CSM）模式下进行了大量压痕测量，随后进行了数据分割、分割数据集的高斯混合建模（GMM）反卷积和结果重新整合。还进行了 X 射线粉末衍射和表面成像伴随的成分分析，以帮助数据解释。结果表明，所研究的页岩由细粒、相对均质的粘土基质和随机嵌入的粗粒固体包裹体组成，其尺寸可达 ~ 100 μm。CSM 模式启用了相位角滞后分析，这是表面粗糙度的有效指标。精确测定微观组成相（如粘土基质、碳酸盐、石英、黄铁矿）和宏观大块页岩的杨氏模量，并通过压痕位置的概率分析，估计了页岩组成相的特征长度。粘土基质和碳酸盐比石英和黄铁矿具有相对较大的特征长度。本研究中提出的数据分析可以提供一个可行的框架，通过对同一块样品的单一类型的测量技术来评估多尺度力学特性以及页岩组成相的特征长度。估计了页岩组成相的特征长度。粘土基质和碳酸盐比石英和黄铁矿具有相对较大的特征长度。本研究中提出的数据分析可以提供一个可行的框架，通过对同一块样品的单一类型的测量技术来评估多尺度力学特性以及页岩组成相的特征长度。估计了页岩组成相的特征长度。粘土基质和碳酸盐比石英和黄铁矿具有相对较大的特征长度。本研究中提出的数据分析可以提供一个可行的框架，通过对同一块样品的单一类型的测量技术来评估多尺度力学特性以及页岩组成相的特征长度。