The creep of rock salt greatly influences the performance and safety of rock salt caverns when they are used as an underground repository for oil, nuclear waste, or other hazardous materials. Creep may cause shearing of casings of oil wells drilled through thick layers of salt rock formation. The crystallographic structure of salt rock grains, in-situ deviatoric stress changes caused by excavation, confining stress from the surrounding environment, and ambient temperature can have a significant impact on the creep behavior of rock salt. Although the creep behavior of polycrystalline rock salt has been extensively studied by many researchers, the creep behavior of single-crystal natural rock salt is not yet fully understood. This paper investigates the influence of crystal orientation, temperature, deviatoric stress, and confining stress on the creep behavior of single-crystal and polycrystalline rock salt. 42 long-term creep experiments with various temperatures, confining stresses, and deviatoric stresses were conducted on natural single-crystal specimens. The temperatures were 20, 100, and 150 °C, the confining stresses were 0.1, 1.0, and 5.0 MPa, and the various deviatoric stresses were applied in different loading directions with respect to the specimen's crystal orientations. Additionally, 18 long-term creep experiments were performed on synthetic polycrystalline specimens with wet grain boundaries at temperatures of 20, 100, and 150 °C, at confining stresses of 0.1, 1.0, and 5.0 MPa, and various deviatoric stresses. The effects of the mentioned experimental conditions on the accumulated axial strain, transient strain rate, and steady-state strain rate during the creep of rock salt were then examined and discussed in detail. Moreover, the influence of temperature, deviatoric stress, and confining stress on the steady-state creep of single crystal rock salt is examined within the context of existing polycrystalline creep data available in the literature.

中文翻译：

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晶体取向、温度、偏应力和围应力对岩盐蠕变的影响


当岩盐穴用作石油、核废料或其他有害物质的地下储存库时，岩盐的蠕变会极大地影响岩盐穴的性能和安全性。蠕变可能导致在厚厚的盐岩层中钻探的油井套管发生剪切。盐岩颗粒的晶体结构、开挖引起的原位偏应力变化、周围环境的限制应力和环境温度都会对岩盐的蠕变行为产生重大影响。尽管许多研究人员已经对多晶岩盐的蠕变行为进行了广泛的研究，但单晶天然岩盐的蠕变行为尚未完全了解。本文研究了晶体取向、温度、偏应力和围压对单晶和多晶岩盐蠕变行为的影响。对天然单晶试件进行了 42 次不同温度、围压和偏应力的长期蠕变试验。温度为 20 °C 、 100 °C 和 150 °C，围应力为 0.1 、 1.0 和 5.0 MPa，各种偏应力根据试件的晶体取向施加在不同的加载方向上。此外，在 20、100 和 150 °C、 0.1 、 1.0 和 5.0 MPa 的围限应力以及各种偏应力下，对具有湿晶界的合成多晶试样进行了 18 次长期蠕变试验。然后，详细研究了上述实验条件对岩盐蠕变过程中累积轴向应变、瞬态应变率和稳态应变率的影响。 此外，在文献中现有的多晶蠕变数据的背景下，研究了温度、偏应力和围压应力对单晶岩盐稳态蠕变的影响。