Study on the deterioration behavior of shale mechanical strength under hydration

doi:10.3969/j.issn.1006-6535.2026.02.016

Abstract

Abstract: In response to the insufficient understanding of rock mass hydration on mechanical strength in underground engineering,a combined approach of rock mechanics experiments and numerical simulation was used,with Longmaxi Formation shale as the study object.Uniaxial compression tests and Abaqus finite element simulations were conducted on rock samples after different soaking times to investigate the impact of hydration on shale mechanical properties and its failure mechanism.The results show that hydration weakens the shale cohesion,thereby significantly reducing its peak stress and elastic modulus.Moreover,as hydration time increases,the failure mode of the rock transitions from brittle to plastic.Meanwhile,there exists a critical point in the deterioration of shale mechanical strength under hydration:the post-deterioration mechanical strength is about 69.19% of that in dry conditions.The findings are of great significance for understanding the hydration-induced mechanical deterioration behavior of underground engineering rock masses and guiding stability evaluations for engineering projects.

Key words: shale, hydration, uniaxial compressive strength, finite element analysis, mechanical strength deterioration

CLC Number:

TE21

SHAO Xianyu, WANG Ke, WANG Zhiqiang, ZHAO Lingyun, LI Zhixuan, TAN Yongsheng, GAO Wei. Study on the deterioration behavior of shale mechanical strength under hydration[J]. Special Oil & Gas Reservoirs, 2026, 33(2): 143-150.

References

[1] KRISHNAN J S,DWIVEDI P,MOHOLKAR V S.Numerical investigation into the chemistry induced by hydrodynamic cavitation[J].Industrial and Engineering Chemistry Research,2006,45(4):1493-1504.
[2] SHAO X,WANG K,ZHAO L,et al.Effects of salinity and driving pressure on water imbibition during shale formation[J].Capillarity,2024,3(11):70-80.
[3] JI W,WANG S,WAN J,et al.Stability analysis of surrounding rock of multi-cavern for compressed air energy storage[J].Advances in Geo-Energy Research,2024,13(3):169-175.
[4] DING Y,YU X,LIU X,et al.Novel analytical model of shale spontaneous imbibition considering the hydration effect[J].Energy & Fuels,2021,35(22):18518-18532.
[5] ZHANG X,LIU W,CHEN J,et al.Large-scale CO₂ disposal/storage in bedded rock salt caverns of China:an evaluation of safety and suitability[J].Energy,2022,249:123727.
[6] YUAN Q,PENG M,YAO H,et al.The internal temperature field of shotcrete in high geothermal tunnel and its effect on microstructures and mechanical properties[J].Construction and Building Materials,2022,335:127507.
[7] ERGULERZ A, ULUSAY R.Water-induced variations in mechanical properties of clay-bearing rocks[J].International Journal of Rock Mechanics & Mining Sciences,2009,46(2):355-370.
[8] COLBACK P S,WIID B L.The influence of moisture content on the compressive strength of rocks[J].Geophysics,1975,10(2):145-156.
[9] MA T S,CHEN P.Study of meso-damage characteristics of shale hydration based on CT scanning technology[J].Petroleum Exploration and Development,2014,41(2):249-256.
[10] LIU Y,YANG C,WANG J,et al.New insights into hydration-induced creep behavior of shale:a comparison study of brittle black shale and clayey oil shale at micro-scale[J].Marine and Petroleum Geology,2022,138:105554.
[11] LIN H,SUN X,YUAN Y,et al.Experimental investigation on the dynamic volume changes of varied-size pores during shale hydration[J].Journal of Natural Gas Science and Engineering,2022,101:104506.
[12] 刘建,乔丽苹,冯夏庭.砂岩水物理化学损伤机制研究[J].岩石力学与工程学报,2007,26(10):2117-2124.
LIU Jian,QIAO Liping,FENG Xiating.Study on damage mechanism of sandstone under hydro-physico-chemical effects[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(10):2117-2124.
[13] 姜永东,鲜学福,许江,等.砂岩单轴三轴压缩试验研究[J].中国矿业,2004,13(4):66-69.
JIANG Yongdong,XIAN Xuefu,XU Jiang,et al.A research on sandstone uniaxial and triaxial compression tests[J].China Mining Magazine,2004,13(4):66-69.
[14] 朱珍德,邢福东,王思敬,等.地下水对泥板岩强度软化的损伤力学分析[J].岩石力学与工程学报,2004,23(增刊2):4739-4743.
ZHU Zhende,XING Fudong,WANG Sijing,et al.Analysis on strength softening of argillite under groundwater by damage mechanics[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(S2):4739-4743.
[15] 薛华庆,周尚文,蒋雅丽,等.水化作用对页岩微观结构与物性的影响[J].石油勘探与开发,2018,45(6):1075-1081.
XUE Huaqing,ZHOU Shangwen,JIANG Yali,et al.Effects of hydration on the microstructure and physical properties of shale[J].Petroleum Exploration and Development,2018,45(6):1075-1081.
[16] 刘向君,熊健,梁利喜.龙马溪组硬脆性页岩水化实验研究[J].西南石油大学学报(自然科学版),2016,38(3):178-186.
LIU Xiangjun,XIONG Jian,LIANG Lixi.Hydration experiment of hard brittle shale of the Longmaxi Formation[J].Journal of Southwest Petroleum University(Science & Technology Edition),2016,38(3):178-186.
[17] 赵二平,贾小兵,龚章龙,等.不同卸荷损伤程度砂岩吸水特性试验研究[J].人民长江,2019,50(6):188-191,224.
ZHAO Erping,JIA Xiaobing,GONG Zhanglong,et al.Experimental research on absorption characteristic of sandstone under different unloading damaged degree[J].Yangtze River,2019,50(6):188-191,224.
[18] 杨圣奇,许帅博,刘振.深部盐水环境下砂岩力学及渗透特性试验研究[J].岩石力学与工程学报,2022,41(2):292-304.
YANG Shengqi,XU Shuaibo,LIU Zhen.Experimental study on mechanical and permeability behaviors of sandstone under deep saline environments[J].Chinese Journal of Rock Mechanics and Engineering,2022,41(2):292-304.
[19] 王浪,邓辉,邓通海,等.泥岩耐崩解性和颗粒粒径相关性的试验研究[J].长江科学院院报,2017,34(8):120-124.
WANG Lang,DENG Hui,DENG Tonghai,et al.Correlation between disintegration resistance and particle size of mudstone[J].Journal of Changjiang River Scientific Research Institute,2017,34(8):120-124.