摘要
冻融循环对岩石的损伤劣化严重影响寒区隧道工程的长期服役性能。为获取裂隙岩石冻融损伤细观特征和冻融后受载力学特性,开展了不同冻融循环次数下饱水裂隙砂岩力学特性试验,推导了冻融过程冻结水体积增量、补给量与冻融循环次数的关系方程。采用颗粒流方法构建一种基于水冰相变体积膨胀理论的岩石冻融劣化模型,通过室内试验验证该模型的可靠性。研究表明:随着冻融循环次数N的增加,试样的力学特性均表现为线性衰减,衰减程度与N呈正相关,且当裂隙倾角为30°时,试样表现的力学特性最弱;裂隙试样在冻融作用下裂隙处的劣化程度大于其他部位,除试样表面颗粒剥落之外,沿裂隙端部产生冻融微裂纹,冻融损伤在试样表层及内部不断积累;颗粒流冻融过程产生的细观微裂纹以张拉裂纹为主,且裂纹数量与N呈正相关,冻融微裂纹由试样表层逐步向内部扩展发育,微裂纹的数量及分布特征影响试样受载破坏形态,且多表现为分布于受载破坏主破裂带附近的次生裂纹破裂带。该研究为冻融作用下岩石损伤劣化过程提供了新思路与新参考,也有助于推动寒区隧道工程灾变预测和长期服役性能评估。
Damage deterioration of rock by freeze-thaw cycles seriously affects the long-term service performance of tunnel projects in cold regions.In order to obtain the fine-scale characteristics of freeze-thaw damage and post-freeze-thaw loading mechanical properties of fissured rocks,tests on the mechanical properties of water-filled fissured sandstones under different levels of freeze-thaw cycles were carried out.Equations were derived to describe the relationship between the volume increment of frozen water,recharge,and the number of freeze-thaw cycles throughout the freeze-thaw process.The particle flow method is used to construct a rock freeze-thaw deterioration model based on the theory of water ice phase transition volume expansion,and the reliability of the model is verified by indoor tests.It is shown that with the increase of the number of freeze-thaw cycles N,the mechanical properties of the specimens show linear attenuation,the degree of attenuation is positively correlated with N.And the mechanical properties of the specimens are the weakest when the fissure inclination angle is 30°.The degradation of fissure specimens due to freezing and thawing is more pronounced than in other parts of the sample.In addition to surface particle flaking,microcracks develop at the ends of the fissures.This results in freeze-thaw damage accumulating both on the surface layer and internally within the specimen.The fine microcracks produced by the freeze-thaw process of granular flow are mainly tensile cracks,and the number of cracks is positively correlated with N.The freeze-thaw microcracks are gradually extended and developed from the surface layer of the specimen to the inner layer,and the number of microcracks and their distribution characteristics affect the load damage morphology of the specimen,and they are mostly manifested as the secondary cracks distributed in the vicinity of the main rupture zone of the load damage rupture zone.This study provides new ideas and references for the damage degradation process of rock under freeze-thaw action,and also helps to promote the prediction of catastrophic changes and long-term service performance assessment of tunnel engineering in cold regions.
作者
孙闯
蒲云波
敖云鹤
陶琦
SUN Chuang;PU Yun-bo;AO Yun-he;TAO Qi(School of Civil Engineering,Liaoning Technical University,Fuxin,Liaoning 123000,China;China Railway 19th Bureau Group Sixth Engineering Co.Ltd.,Wuxi,Jiangsu 214000,China)
出处
《岩土力学》
北大核心
2025年第8期2339-2352,共14页
Rock and Soil Mechanics
基金
国家自然科学基金(No.51704144)
辽宁省“兴辽英才计划”资助项目(No.XLYC1807107)。
关键词
冻融循环
预制裂隙
离散元法
损伤衰减
破裂演化
freeze-thaw cycles
prefabricated fissures
discrete element method
damage attenuation
fracture evolution
