Rocksalt and mudstone are usually under common stress in salt storage caverns, resulting in different mechanical properties from pure rocksalt and mudstone. To accurately obtain the creep mechanical characteristics of rocksalt-mudstone combined body, we have made three different combinations. The long-term creep experiment of bedded rocks can more closely reflect the long-term mechanical behavior of surrounding rock of salt storage caverns. The experimental results indicated that the long-term creep curve of the combined body includes initial and steady creep stages, and even includes accelerated creep stage. The strain of mudstone layer in the combined body was lower than that of rocksalt because of the higher strength. With the increase of the height ratio of mudstone, the creep strain of the combined body and each rock layer decreased, but the creep rate increased. A new nonlinear creep-damage constitutive model was proposed, which can well describe the creep evolution characteristics of the experiment. Compared with the fitting curves of classical Burgers and Nishihara creep constitutive models, it is revealed that the proposed model is most consistent with the experimental data. The duration of the long-term creep experiment under lower stress has a highly significant effect on the accuracy of predicting rock creep results. This research will contribute to a deeper understanding of the long-term creep characteristics of bedded rocks in salt storage caverns.

储盐洞室中岩盐和泥岩通常承受共同的应力，导致与纯岩盐和泥岩不同的力学性质。为了准确获得岩盐-泥岩组合体的蠕变力学特性，我们做了三种不同的组合。层状岩体长期蠕变试验更能反映储盐洞室围岩长期力学行为。实验结果表明，组合体的长期蠕变曲线包括初始蠕变阶段和稳态蠕变阶段，甚至包括加速蠕变阶段。组合体中泥岩层的应变低于岩盐，因为其强度较高。随着泥岩高度比的增加，组合体和各岩层的蠕变应变减小，但是蠕变率增加了。提出了一种新的非线性蠕变-损伤本构模型，可以很好地描述实验的蠕变演化特征。与经典 Burgers 和 Nishihara 蠕变本构模型的拟合曲线相比，表明该模型与实验数据最一致。在较低应力下长期蠕变实验的持续时间对预测岩石蠕变结果的准确性具有非常显着的影响。这项研究将有助于更深入地了解储盐洞穴中层状岩石的长期蠕变特征。与经典 Burgers 和 Nishihara 蠕变本构模型的拟合曲线相比，表明该模型与实验数据最一致。在较低应力下长期蠕变实验的持续时间对预测岩石蠕变结果的准确性具有非常显着的影响。这项研究将有助于更深入地了解储盐洞穴中层状岩石的长期蠕变特征。与经典 Burgers 和 Nishihara 蠕变本构模型的拟合曲线相比，表明该模型与实验数据最一致。在较低应力下长期蠕变实验的持续时间对预测岩石蠕变结果的准确性具有非常显着的影响。这项研究将有助于更深入地了解储盐洞穴中层状岩石的长期蠕变特征。