Failure mechanisms of lunar regolith slopes under low-gravity conditions
ZHANG Jinwang1, 2, GAO Yishuo1, 2, WANG Jiachen1, 2*, CHENG Dongliang1, 2, SUN Shuwei1, 2, HE Geng1, 2, WAN Xiaohang1, 2
(1. School of Energy and Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China;
2. Engineering Research Center of Green and Intelligent Mining for Thick Coal Seam, Ministry of Education, China University of Mining and Technology (Beijing), Beijing 100083, China)
Abstract：To investigate the failure mechanisms of lunar soil slopes under lunar surface conditions and to promote the adaptation of terrestrial shallow mining technologies to the lunar environment, this study systematically analyzes the effects of gravity and Van der Waals forces on slope failure mechanisms through a combination of discrete element numerical simulations and physical bottom friction tests. Based on the two-dimensional particle flow code (PFC2D), a rolling resistance mechanism and van der Waals forces are incorporated into the contact model of lunar soil particles. By assigning differentiated rolling resistance coefficients to particles of different sizes and considering adhesive effects, the particle shape effects and inter-molecular forces are reasonably characterized. A dynamic static combined calibration mechanism ensures the accuracy of the model, enabling numerical simulations of rapid slope excavation processes under different gravity conditions. On this basis, physical validation is conducted using a self-developed experimental platform for mining slope stability under low-gravity lunar surface conditions and Lunar Regolith Simulant. The mutually validated results of numerical simulations and bottom friction tests indicate that without considering factors such as the high vacuum and extreme temperature differences on the lunar surface, the slope exhibits significant subsidence with the failure mode primarily characterized by progressive shallow particle flow under low-gravity lunar surface conditions. In contrast, under terrestrial gravity conditions, the failure is mainly manifested as “tensile-shear” failure. The influence of van der Waals forces on particle motion is gravity-dependent, becoming more pronounced under low-gravity conditions, where it promotes particle motion in the form of “quasi-clusters” and reduces the dispersion effect during motion. The findings of this study can provide a reference for slope stability analysis and disaster prevention in lunar resource extraction.
[1] 欧阳自远. 天体化学[M]. 北京：科学出版社，1988：1–322.(OUYANG Ziyuan. Research on cosmochemistry[M]. Beijing：Science Press，1988：1–322.(in Chinese))
[2] 中国科学院地球化学研究所. 月质学研究进展[M]. 北京：科学出版社，1977：1–312.(Institute of Geochemistry，Chinese Academy of Sciences. Research on advances in lunar petrology[M]. Beijing：Science Press，1977：1–312.(in Chinese))
[3] HEIKEN G，VANIMAN D，FRENCH B M. Lunar sourcebook：A user′s guide to the Moon[M]. Cambridge：Cambridge University Press，1991：121–155.
[4] 欧阳自远，邹永廖，李春来，等. 月球某些资源的开发利用前景[J]. 地球科学，2002，27(5)：498–503.(OUYANG Ziyuan，ZOU Yongliao，LI Chunlai，et al. Prospects for the utilization of certain lunar resources[J]. Earth Science，2002，27(5)：498–503.(in Chinese))
[5] HEAD J W. Lava flooding of ancient planetary crusts：Geometry，thickness，and volumes of flooded lunar impact basins[J]. Moon and the Planets，1982，26(1)：61–88.
[6] GIGUERE T A，TAYLOR G J，HAWKE B R，et al. The titanium contents of lunar mare basalts[J]. Meteoritics and Planetary Science，2000，35(1)：193–200.
[7] JOLLIFF B L，GILLIS J J，HASKIN L A，et al. Major lunar crustal terranes：Surface expressions and crust-mantle origins[J]. Journal of Geophysical Research，2000，105(E2)：4 197.
[8] HASKIN L A，GILLIS J J，KOROTEV R L，et al. The materials of the lunar Procellarum KREEP Terrane：A synthesis of data from geo-morphological mapping，remote sensing，and sample analyses[J]. Journal of Geophysical Research：Planets，2000，105(E8)：20 403–20 415.
[9] QI S W，LI L H，HOU X K，et al. Strongly cohesive lunar soil identified at the Chang?e-6 landing site[J]. Nature Astronomy，2026，10(2)：214–223.
[10] PERKO H A，NELSON J D，SADEH W Z. Surface clean lines effect on lunar soil shear strength[J]. Journal of Geotechnical and Geoenvironmental Engineering，2001，127(4)：371–383.
[11] LUO A，CUI Y F，NIE J Y，et al. Effects of adhesion and particle shape on mechanical behaviors of lunar regolith under low stress condition-3D DEM study[J]. Computers and Geotechnics，2024，175：106661.
[12] 石安宁，蒋明镜，王思远. 基于粒形特征影响的月壤静力学及流动特性离散元研究[J]. 岩土工程学报，2025，47(4)：749–758.(SHI Anning，JIANG mingjing，WANG Siyuan. Distinct element method for static and flow mobility characteristics of lunar regolith based on particle shape characteristics[J]. Journal of Geotechnical Engineering，2025，47(4)：749–758.(in Chinese))
[13] BUI H H，KOBAYASHI T，FUKAGAWA R，et al. Numerical and experimental studies of gravity effect on the mechanism of lunar excavations[J]. Journal of Terramechanics，2009，46( 3)：115–124.
[14] 石安宁，蒋明镜，杨耿超，等. 太空环境下颗粒材料流动特性离散元分析：立柱坍塌试验[J]. 岩土工程学报，2025，47(12)：2 488–2 497.(SHI Anning，JIANG mingjing，YANG Gengchao，et al. Discrete element analysis of flow characteristics of particle materials in space environment: stand collapse experiment[J]. Chinese Journal of Geotechnical Engineering，2025，47(12)：2 488–2 497.(in Chinese))
[15] 廖优斌，蒋明镜，陈有亮，等. 不同坡角下月壤滑坡机理的离散元分析[J]. 水资源与水工程学报，2018，29(2)：194–200.(LIAO Youbin，JIANG Mingjing，CHEN Youliang，et al. Discrete element analysis of landslide mechanism on lunar soil induced by different slope angles[J]. Journal of Water Resources and Water Engineering，2018，29(2)：194–200.(in Chinese))
[16] ZHENG H，HUANG Y. Model tests on flow slide of lunar regolith simulant[J]. Environmental Earth Sciences，2014，73(8)：1–7.
[17] 邓佳音，程维明，刘樯漪，等. 月表地貌起伏形态分异特征及分级标准研究[J]. 地理学报，2022，77(7)：1 794–1 807.(DENG Jiayin，CHENG Weiming，LIU Qiangyi，et al. Morphological differentiation characteristics and classification criteria of lunar surface relief amplitude[J]. Acta Geographica Sinica，2022，77(7)：1 794–1 807.(in Chinese))
[18] XIAO L，ZHU P M，FANG G Y，et al. A young multilayered terrane of the northern Mare Imbrium revealed by Chang'E-3 mission[J]. Science，2015，347(6227)：1 221–1 225.
[19] SCAIONI M，YORDANOV V，BRUNETTI M T，et al. Recognition of landslides in lunar impact craters[J]. European Journal of Remote Sensing，2017，51(1)：47–61.
[20] 乔 乐，刘小倩，赵健楠，等. 月球雨海地区三个着陆点的地质特征对比研究[J]. 中国科学：物理学 力学 天文学，2016，46(2)：9 603–9 615.(QIAO Le，LIU Xiaoqian，ZHAO Jiannan，et al. comparative study on geological characteristics of three landing sites in the rainy sea region of the Moon[J]. Science China：Physics，Mechanics and Astronomy，2016，46(2)：9 603–9 615.(in Chinese))
[21] 周增坡，程维明，万 丛，等. 月球正面撞击坑的空间分布特征分析[J]. 地球信息科学学报，2012，14(5)：618–626.(ZHOU Zengbo，CHENG Weiming，WAN Cong，et al. Analysis of the spatial distribution characteristics of impact craters on the lunar surface[J]. Journal of Geoinformation Science，2012，14(5)：618–626.(in Chinese))
[22] 欧阳自远. 月球科学概论[M]. 北京：中国宇航出版社，2005：280–292.(OUYANG Ziyuan. An introduction to Lunar science[M]. Beijing：China Space Science Press，2005：280–292.(in Chinese))
[23] JIANG M J，SHEN Z F，THORNTON C，et al. Microscopic contact model of lunar regolith for high efficiency discrete element analyses[J]. Computers and Geotechnics，2013，54：104–116.
[24] WU Q X，JIA Y F，WU H，et al. Macro-and micro-mechanical behavior of CSU-LRS-1 lunar soil simulant under true triaxial loading path[J]. Granular Matter，2024，26：63.
[25] 蒋明镜. 现代土力学研究的新视野——宏微观土力学[J]. 岩土工程学报，2019，41(2)：195–254.(JIANG Mingjing. New paradigm for modern soil mechanics：Geomechanics from micro to macro[J]. Chinese Journal of Geotechnical Engineering，2019，41(2)：195–254.(in Chinese))
[26] 王思远，蒋明镜. 基于嫦娥五号月壤粒形特征的离散元模拟方法[J]. 岩土工程学报，2024，46(4)：833–842.(WANG Siyuan，JIANG Mingjing. Lunar regolith simulations with discrete element method based on Chang?E–5 mission's lunar soil particle morphology[J]. Chinese Journal of Geotechnical Engineering，2024，46(4)：833–842.(in Chinese))
[27] ZHOU N，CHEN J，TIAN N，et al. Calibration of discrete element method parameters for a high-fidelity lunar regolith simulant considering the effects of realistic particle shape[J]. Materials，2024，17：4 789.
[28] ZHU J Z，ZOU M，LIU Y S，et al. Measurement and calibration of DEM parameters of lunar soil simulant[J]. Acta Astronautics，2022，191：169–177.
[29] MITCHELL J K，BROMWELL L G，DAVID C W，et al. Soil mechanical properties at the Apollo 14 site[J]. Journal of Geophysical Research，1972，77(29)：5 641–5 664.
[30] THORNTON C. Numerical simulations of deviatoric shear deformation of granular media[J]. Géotechnique，2000，50(1)：43–53.
[31] 张嘎，张建民. 基于瑞典条分法的应变软化边坡稳定性评价方法[J]. 岩土力学，2007，28(1)：12–16.(ZHANG Ga，ZHANG Jianmin. Evaluation method for stability of softening slope based on Swedish element method[J]. Rock and Soil Mechanics，2007，28(1)：12–16.(in Chinese))
[32] 王家臣，孙书伟. 露天矿边坡工程[M]. 北京：科学出版社，2016：274–276.(WANG Jiachen，SUN Shuwei. Open-pit mine slope engineering[M]. Beijing: Science Press，2016：274–276.(in Chinese))
[33] 孙书伟，胡家冰，刘 流，等. 抚顺西露天矿边坡岩体结构与灾害预报模型研究[J]. 岩石力学与工程学报，2025，44(7)：1 695–1 708. (SUN Shuwei，HU Jiabin，LIU Liu，et al. Investigations of the rock mass structure and disaster prediction model of slopes in the Fushun west open pit mine[J]. Chinese Journal of Rock Mechanics and Engineering，2025，44(7)：1 695–1 708.(in Chinese))
[34] 孙书伟，李 圆，杨晓锐，等. 不同岩层倾角顺倾层状岩质边坡破坏机制研究[J]. 岩石力学与工程学报，2024，43(7)：1 607–1 620. (SUN Shuwei，LI Yuan，YANG Xiaorui，et al. Study on the failure mechanism of rock slopes with dipped layered structures under various rock dip conditions[J]. Chinese Journal of Rock Mechanics and Engineering, 2024，43(7)：1 607–1 620.(in Chinese))
[35] 周宁希，陈 健，黄珏皓，等. 磁性高钛模拟月壤IRSM-1的研制及其性质研究[J]. 岩土工程学报，2023，45(增1)：110–113.(ZHOU Ningxi，CHEN Jian，HUANG Juehao，et al. Development and properties of a magnetic high-titanium lunar regolith simulant IRSM-1[J]. Chinese Journal of Geotechnical Engineering，2023，45(Supp.1)：110–113.(in Chinese))
[36] 邬 凯，周立荣，张 乐，等. 饱水软化下顺层边坡原状滑带土强度特性研究[J]. 土木工程学报，2023，56(增1)：24–34.(WU Kai，ZHOU Lirong，ZHANG Le，et al. Study on strength behavior of undisturbed slip zone soil in bedding slope with saturated softening[J]. China Civil Engineering Journal，2023，56(Supp.1)：24–34.(in Chinese))
[37] 孙书伟，庞 博，刘 流，等. 露天矿排土场土工格栅加固机制试验研究[J]. 岩石力学与工程学报，2022，41(11)：2 320–2 336.(SUN Shuwei，PANG Bo，LIU Liu，et al. Experimental research on reinforcement mechanism of geogrid in open-pit dump[J]. Chinese Journal of Rock Mechanics and Engineering，2022，41(11)：2 320–2 336.(in Chinese))
[38] XIAO Z Y，XIAO Z X，ZHANG W M，et al. Active landslides on the Moon[J]. National Science Review，2025，12：nwaf384.
[39] KOCHUBEY X，IVANOV M A. Estimation of the rate of slope processes and morphological variability of kilometer-sized impact craters on the Moon[J]. Solar System Research，2024，58：57–67.
[40] THAKER A D，PATEL S M，SOLANKI P M. Morphological analysis and mapping of complex craters of Copernican age：Crookes，Ohm and Stevinus[J]. Planetary and Space Science，2020，184：104856.
2026, Vol. 45 
