Abstract：To accurately predict the collapse step distance of mudstone interlayers during cavern leaching and ensure the stability of salt cavern gas storage facilities, this study conducts an in-depth analysis of the structural characteristics and mechanical properties of mudstone interlayers, establishing a predictive model for interlayer fracture. Macroscopic analysis and point load tests on mudstone interlayer samples from Submember 3b of Member 3 of the Buxin Formation in the Sanshui District salt mine revealed the following: (1) the structural characteristics of the mudstone interlayer vary significantly from top to bottom, with the lower section developing multi-angle fractures (partially filled with salt rock), while the upper part remains dense; (2) consequently, the interlayer is categorized into an upper high-strength mudstone and a lower low-strength mudstone, with point load tests confirming that the uniaxial compressive strength of the high-strength mudstone is approximately 5.5 times that of the low-strength mudstone; (3) under brine soaking, the high-strength mudstone exhibits significant softening effects within the initial 14 days, after which its strength tends to stabilize; the long-term strength is primarily influenced by intrinsic interlayer characteristics, such as the proportion of high-strength mudstone and interlayer thickness. Based on these properties, the progressive fracture mechanism of the mudstone interlayer is revealed, which can be divided into three stages: low-strength mudstone fracture, high-strength mudstone fracture, and operational-stage fracture. Ultimately, a fracture distance prediction formula is established that comprehensively considers soaking time and interlayer characteristics (high-strength mudstone proportion and thickness). The study clarifies that: (1) buckling failure occurs in the interlayer when the high-strength mudstone proportion exceeds a critical value (approximately 0.2); (2) when the high-strength mudstone proportion is relatively low, non-buckling failure is more likely to occur. These research findings provide a theoretical basis for predicting and controlling interlayer collapse during the leaching of salt cavern gas storage facilities.
孟恒磊，杨伟峰*，刘 星，郑鑫源，王宇乐. 盐穴储气库泥岩夹层特性及建腔期夹层破断模型的构建[J]. 岩石力学与工程学报, 2026, 45(1): 250-265.
MENG Henglei, YANG Weifeng*, LIU Xing, ZHENG Xinyuan, WANG Yule. Characteristics of mudstone interlayers and mechanical failure model development during salt cavern gas storage construction. , 2026, 45(1): 250-265.
[1] 康燕飞. 盐岩损伤愈合与再固结特性研究[博士学位论文][D]. 重庆：重庆大学，2023.(KANG Yanfei. Research on the healing and re-solidification characteristics of salt rock damage[Ph. D. Thesis][D]. Chongqing：Chongqing University，2023.(in Chinese))
[2] 中华人民共和国自然资源部.《中国矿产资源报告》[DB/OL]. 2024.https://chinacma.org.cn/static/upload/file/20250604/1749013902101555.pdf.(Ministry of Natural Resources，PRC，"China mineral resources report"[DB/OL]. 2024. https://chinacma.org.cn/static/upload/file/20250604/1749013902101555.pdf.(in Chinese))
[3] YANG C，WANG T，LI Y，et al. Feasibility analysis of using abandoned salt caverns for large-scale underground energy storage in China[J]. Applied Energy，2015，137：46–48.
[4] 杨春和，贺 涛，王同涛. 层状盐岩地层油气储库建造技术研发进展[J]. 油气储运，2022，41(6)：614–624.(YANG Chunhe，HE Tao，WANG Tongtao. Research and development progress of technology for building oil and gas reservoirs in layered salt rock strata[J]. Oil and Gas Storage and Transportation，2022，41(6)：614–624.(in Chinese))
[5] 李建君. 中国地下储气库发展现状及展望[J]. 油气储运，2022，41(7)：780–786.(LI Jianjun. Current situation and prospects of China's underground gas storage facilities development[J]. Oil and Gas Storage and Transportation，2022，41(7)：780–786.(in Chinese))
[6] 施锡林，李银平，杨春和，等. 盐穴储气库水溶造腔夹层垮塌力学机制研究[J]. 岩土力学，2009，30(12)：3 615–3 620.(SHI Xilin，LI Yinping，YANG Chunhe，et al. Research on the mechanical mechanism of collapse of water-soluble cavity interlayers in salt cavern gas storage facilities[J]. Rock and Soil Mechanics，2009，30(12)：3 615–3 620.(in Chinese))
[7] 施锡林，李银平，杨春和，等. 卤水浸泡对泥质夹层抗拉强度影响的试验研究[J]. 岩石力学与工程学报，2009，28(11)：2 301–2 308. (SHI Xilin，LI Yinping，YANG Chunhe，et al. Experimental study on the effect of salt water soaking on the tensile strength of mud-like interlayers[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(11)：2 301–2 308.(in Chinese))
[8] 施锡林，李银平，杨春和，等. 多夹层盐矿油气储库水溶建腔夹层垮塌控制技术[J]. 岩土工程学报，2011，33(12)：1 957–1 963.(SHI Xilin，LI Yinping，YANG Chunhe，et al. Control technology for water-soluble cavity-laying interlayers collapse in multi-layered salt mines for oil and gas storage[J]. Chinese Journal of Geotechnical Engineering，2011，33(12)：1 957–1 963.(in Chinese))
[9] 孟 涛，梁卫国，陈跃都，等. 层状盐岩溶腔建造过程中石膏夹层周期性垮塌理论分析[J]. 岩石力学与工程学报，2015，34(增1)：3 267–3 273.(MENG Tao，LIANG Weiguo，CHEN Yuedu，et al. Theoretical analysis on the periodic collapse of gypsum interlayers during the formation of layered salt rock reservoirs[J]. Chinese Journal of Rock Mechanics and Engineering，2015，34(Supp.1)：3 267–3 273.(in Chinese))
[10] 王永春. 平顶山盐穴储气库夹层稳定性及垮塌灾害性研究[硕士学位论文][D]. 郑州：郑州大学，2019.(WANG Yongchun. Research on the stability of interlayers and collapse disaster of salt cave gas storage wells in Pingdingshan[M. S. Thesis][D]. Zhengzhou：Zhengzhou University，2019.(in Chinese))
[11] 王志荣，王永春，高志俭，等. 平顶山地下盐穴储气库泥岩夹层稳定性评价[J]. 高校地质学报，2019，25(1)：116–124.(WANG Zhirong，WANG Yongchun，GAO Zhijian，et al. Evaluation of the stability of mudstone interlayers in Pingdingshan underground salt cavern gas storage reservoirs[J]. Journal of Geology in Colleges，2019，25(1)：116–124.(in Chinese))
[12] MENG T，HU Y，FANG R，et al. Weakening mechanisms of gypsum interlayers from Yunying salt cavern subjected to a coupled thermo-hydro-chemical environment[J]. Journal of Natural Gas Science and Engineering， 2016，30：77–89.
[13] WANG T，YANG C，SHI X，et al. Failure analysis of thick interlayer from leaching of bedded salt caverns[J]. International Journal of Rock Mechanics and Mining Sciences，2015，73：175–183.
[14] WANG Y，LIU J. Critical length and collapse of interlayer in rock salt natural gas storage[J]. Advances in Civil Engineering，2018，2018(1)：865–880.
[15] BEKENDAM R，PAAR W. Induction of subsidence by brine removal[C]// Proceedings of the SMRI Fall Meeting. [S. l.]：[s. n.]，2002：1–12.
[16] ZHANG G，LIU Y，WANG T，et al. Research on anchoring effect and failure mechanism of hard interlayers in the cavern pillar of underground gas storage in bedded salt formations[J]. Journal of Energy Storage，2022，55：105–114.
[17] SUO J，FAN J，JIANG D，et al. Experimental study on fatigue failure properties of mudstone interlayers under discontinuous loading in salt cavern gas storage[J]. Engineering Failure Analysis，2024，159：108–143.
[18] WU F，MENG T，CAO K，et al. Influence of layering and fracture angles on the performance of salt-gypsum composites：implications for the safety of underground energy storage[J]. Energies，2025，18(9)：22–87.
[19] WEI X，HUANG W，SU X，et al. Failure mode characteristic of rocks containing a weak interlayer with different thickness and dip angles based on discrete-element method[J]. International Journal of Geomechanics，2025，25(3)：04025014.
[20] NIAN Y，WU S，HAN S. Numerical simulation of mechanical and fracture behavior of composite rock containing weak interlayers[J]. Computational Particle Mechanics，2024，11(4)：1 681–1 694.
[21] HU J，WEN H，XIE Q，et al. Effects of seepage and weak interlayer on the failure modes of surrounding rock：model tests and numerical analysis[J]. Royal Society Open Science，2019，6(9)：190790.
[22] LI J，TANG Y，SHI X，et al. Modeling the construction of energy storage salt caverns in bedded salt[J]. Applied Energy，2019，255：113866.
[23] ZHAO N，ZHANG Y，MIAO H，et al. Study on the creep and fracture evolution mechanism of rock mass with weak interlayers[J]. Advances in Materials Science and Engineering，2022，2022(1)：5004306.
[24] GUO J C，LUO B，ZHU H Y，et al. Multilayer stress field interference in sandstone and mudstone thin interbed reservoir[J]. Journal of Geophysics and Engineering，2016，13(5)：775–785.
[25] ZHANG Z，WANG T. Failure modes of weak interlayers with different dip angles in red mudstone strata，Northwest China[J]. Bulletin of Engineering Geology and the Environment，2023，82(5)：156.
[26] 方 龙，秦占杰，石国成，等. 泰国暖颂钾盐矿床粗粒岩盐沉积特征及其成因研究[J]. 盐湖研究，2024，32(1)：107–119.(FANG Long，QIN Zhanjie，SHI Guocheng，et al. Study on the characteristics and genesis of coarse-grained rock salt deposition in the Namsong potassium salt deposit in Thailand[J]. Salt Lake Research，2024，32(1)：107–119.(in Chinese))
[27] 中华人民共和国国家标准编写组. GB/T 50266—2013工程岩体试验方法标准[S]. 北京：中国计划出版社，2013.(The National Standards Compilation Groups of People's Republic of China. GB/T 50266—2013 Standard for test methods of rock mass in engineering[S]. Beijing：China Planning Press，2013.(in Chinese))
[28] 中华人民共和国国家标准编写组. GB/T 50218—2014工程岩体分级标准[S]. 北京：中国计划出版社，2014.( The National Standards Compilation Groups of People's Republic of China. GB/T 50218—2014Standard for classification of rock mass in engineering[S]. Beijing：China Planning Press，2014.(in Chinese))
[29] LI D，WONG L N Y. Point load test on meta-sedimentary rocks and correlation to UCS and BTS[J]. Rock Mechanics and Rock Engineering，2013，46：889–896.
[30] LI W，ZHU C，HAN J，et al. Thermodynamic response of gas injection and withdrawal process in salt cavern for underground gas storage[J]. Applied Thermal Engineering，2019，163：114–180.
2026, Vol. 45 
