岩土力学2023，Vol.44Issue(12)：3602-3616,15.DOI:10.16285/j.rsm.2023.0448
基于离散元法模拟的冻融砂岩细观破裂演化特征研究
Meso-fracture evolution characteristics of freeze-thawed sandstone based on discrete element method simulation
摘要
Abstract
To investigate the mesoscopic damage accumulation and the loading-induced fracture process in freeze-thawed rocks,a method coupling water-ice particle phase transition and expansion based on the discrete element method is proposed.The rock freeze-thaw process is simulated using a particle flow program,and the reliability of the simulation results is verified through laboratory experiments.The frost heave evaluation indexλvof pore water particles is quantitatively characterized,and a functional relationship between λv and the number of freeze-thaw cycles N is established.Furthermore,the fracture characteristics and the evolution of microcrack,displacement field and force chain field in freeze-thawed rocks during the loading process are evaluated.The results show that:(1)The volumetric expansion of pore water in the rock and continuous water replenishment are the essential causes of rock damage under freeze-thaw treatments.Microcracks in the samples are dominated by tensile cracks during the freeze-thaw process,exhibiting an"initially slow,then fast"evolutionary trend,with more significant displacement of rock particles on the periphery than those in the interior.(2)The number of microcracks in the samples under loading exhibits a"slow→gradual→rapid"growth trend.The numbers of freeze-thaw cycles positively correlated with the number of microcracks but negatively correlated with the microcrack initiation stressσi.(3)The fracture process and morphology of the samples differ significantly before and after freeze-thaw treatment.When the load approaches the peak stress σf,there are"abnormal signals"in the microcrack distribution,displacement field and force chain field,which can serve as a precursor to failure identification.Under the influence of freeze-thaw cycles,the spatial arrangement of microcracks inside the samples becomes more complex,and the fracture mode transitions from dominance by tensile microcracks to dominance by mixed tensile-shear microcracks.This study provides a new idea and method for exploring the failure behavior of freeze-thawed rocks.关键词
离散元/冻融循环/颗粒流/细观损伤/单轴压缩/破裂演化Key words
discrete element method/freeze-thaw cycles/particle flow/mesoscopic damage/uniaxial compression/fracture evolution分类
土木建筑引用本文复制引用
宋勇军,孙银伟,李晨婧,杨慧敏,张磊涛,谢丽君..基于离散元法模拟的冻融砂岩细观破裂演化特征研究[J].岩土力学,2023,44(12):3602-3616,15.基金项目
国家自然科学基金(No.42277182,No.11972283).This work was supported by the National Natural Science Foundation of China(42277182,11972283). （No.42277182,No.11972283）
