Knowledge of the internal state of rock is key to anticipate its rheological response and susceptibility to external factors. Time‐dependent failure in rock is controlled by internal state changes, like damage accumulation or strength degradation. But assessing internal states and changes thereof, nondestructively and independent of external forcing is not straightforward. Residual strains, measured with neutron diffraction techniques are used as a proxy for the internal state in material sciences. We investigated its potential for progressive rock failure by measuring residual strain states of an untested and three mechanically and chemomechanically pretested Carrara marble samples. We collected neutron diffraction data for three crystal lattice planes {10̅14}, {0006}, and {11̅20}. Measurements showed an initial overall contractional spatially homogeneous residual unit cell volume strain state of about −400 μstrain, though magnitudes were strongly partitioned among measured crystal lattice planes. However, they are equal within the spatial orientations of the intact sample. For the pretested samples, the induction and relaxation of strains varied spatially with the pretesting stress field and environmental conditions. The vertical extent of superposition of the initial residual strain state was greatest in wet samples, the magnitude of induced extensional strain highest in the dry sample. This indicates chemomechanically enhanced subcritical crack growth with concomitant residual strain relaxation as well as the mitigation of extensional strain built up by the presence of water during pretesting. Our experiments show that residual strain has a significant potential to provide insights into past and actual internal states to anticipate progressive rock failure.

中文翻译：

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通过测量带有中子衍射的残余应变来约束卡拉拉大理石进行性岩石破坏中的内部状态

了解岩石的内部状态对于预测其流变响应和对外部因素的敏感性至关重要。岩石中随时间变化的破坏受内部状态变化的控制，例如损伤累积或强度下降。但是，无损且独立于外部强迫评估内部状态及其变化并非易事。用中子衍射技术测得的残余应变在材料科学中被用作内部状态的代表。我们通过测量未经测试的卡拉拉大理石样品和三个经过机械和化学力学预测试的大理石样品的残余应变状态，研究了其潜在的岩石破坏潜力。我们收集了三个晶格平面{10̅14}，{0006}和{11̅20}的中子衍射数据。测量显示初始的整体收缩空间均质残余单位晶胞体积应变状态约为-400μs应变，尽管大小在所测量的晶格平面之间强烈分配。但是，它们在完整样本的空间方向上是相等的。对于预测试样品，应变的诱导和松弛随预测试应力场和环境条件而在空间上变化。初始残余应变状态的垂直叠加程度在湿样品中最大，在干样品中诱导拉伸应变的幅度最高。这表明化学机械增强了亚临界裂纹的发展，同时伴随着残余应变的松弛以及在预测试期间因水的存在而建立的拉伸应变的减轻。