为探究冻融岩石细观损伤累积及受载破裂过程，基于离散元提出一种水冰颗粒相变耦合膨胀方法，借助颗粒流程序实现岩石冻融过程模拟，结合室内试验验证模拟结果的可靠性，定量表征孔隙水颗粒冻胀评价指标λv，建立λv与冻融循环次数N之间的函数关系，并对冻融岩石受载过程中微裂纹−位移场−力链场演化及破裂特征进行评估。结果表明：（1）冻融循环作用下岩石内部孔隙水体积膨胀及持续补水是造成其损伤的本质原因；冻融过程中试样细观微裂纹由拉伸裂纹主导，呈“先慢后快”趋势演化，且外围岩石颗粒位移较内部更显著。（2）试样受载时微裂纹呈“慢→缓→陡”发展，冻融循环次数N 与受载产生的微裂纹数量呈正相关，但与微裂纹起裂应力σi却呈负相关。（3）冻融前后试样破裂过程与形态明显不一，受载趋于峰值强度σf 时，试样微裂纹分布−位移场−力链场有“异常信号”出现，可作为破坏前兆识别信息；冻融循环影响下，试样内部微裂纹空间排布方式更为复杂，由拉伸微裂纹主导破裂向拉−剪混合微裂纹主导转变。该研究可为探索冻融岩石破坏行为提供一种新的思路和方法。 To investigate themesoscopic damage accumulation and the loading-induced fracture process in freeze-thawedrocks

a method coupling water-ice particle phase transition and expansionbased on the discrete element method is proposed. The rock freeze-thaw processis simulated using a particle flow program

and the reliability of thesimulation results is verified through laboratory experiments. The frost heaveevaluation index λv of pore waterparticles is quantitatively characterized

and a functional relationshipbetween λv and the number offreeze-thaw cycles N is established. Furthermore

the fracturecharacteristics and the evolution of microcrack

displacement field and forcechain field in freeze-thawed rocks during the loading process are evaluated.The results show that: (1) The volumetric expansion of pore water in the rockand continuous water replenishment are the essential causes of rock damageunder freeze-thaw treatments. Microcracks in the samples are dominated bytensile cracks during the freeze-thaw process

exhibiting an “initially slow

then fast” evolutionary trend

with more significant displacement of rockparticles on the periphery than those in the interior. (2) The number of microcracksin the samples under loading exhibits a “slow→gradual→rapid” growthtrend. The numbers of freeze-thaw cycles positively correlated with the numberof microcracks but negatively correlated with the microcrack initiation stress σi . (3) The fracture process and morphology of the samplesdiffer significantly before and after freeze-thaw treatment. When the loadapproaches the peak stress σf

there are “abnormal signals” in the microcrack distribution

displacement field and force chain field

which can serve as a precursor tofailure identification. Under the influence of freeze-thaw cycles

the spatialarrangement of microcracks inside the samples becomes more complex

and thefracture mode transitions from dominance by tensile microcracks to dominance bymixed tensile-shear microcracks. This study provides a new idea and method forexploring the failure behavior of freeze-thawed rocks.