土/岩体的冻融回滞及水分迁移综合机制研究  

Research on the comprehensive mechanism of freeze-thaw hysteresis and water migration of soil/rock

作　　者：陈汉青 程桦[1,2,3] 曹璐 荣传新[1] 姚直书[1] 蔡海兵[1] CHEN Hanqing;CHENG Hua;CAO Lu;RONG Chuanxin;YAO Zhishu;CAI Haibing(College of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan,Anhui 232001,China;College of Resources and Environment,Anhui University,Hefei,Anhui 230601,China;Anhui Province Key Laboratory of Building Structure and Underground Engineering,Anhui Jianzhu University,Hefei,Anhui 230601,China;College of Economics and Management,Anhui University of Science and Technology,Huainan,Anhui 232001,China)

机构地区：[1]安徽理工大学土木建筑学院,安徽淮南232001 [2]安徽大学资源与环境学院,安徽合肥230601 [3]安徽建筑大学安徽省建筑结构与地下工程重点实验室,安徽合肥230601 [4]安徽理工大学经济管理学院,安徽淮南232001

出　　处：《岩石力学与工程学报》2022年第11期2365-2375,共11页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51874005,51878005,51778004)。

摘　　要：为阐明土/岩体在冻融过程中产生的冻融回滞与不均匀冻胀现象,对冻融回滞与冻融水分迁移机制开展研究。首先,根据广义Clapeyron方程和Gibbs-Thomson方程,给出任意弯曲界面液相水的冻结温度方程,构建毛细管的冻结与融化模型;据此,引入抗冻性较差的“主干–旁枝型”孔隙结构,构建毛细–薄膜水的冻融回滞三角形模型;最后,通过低场核磁共振试验,验证该模型的正确性。研究表明:(1)由于冻融边界曲率差异,致使毛细压力为界面压力2倍,造成融化温度仅为冻结温度的1/2;(2)界面压力仅与边界条件有关,与冻融过程无关;(3)界面压力与理论冰压、理论吸力、迁移驱动力和表面吸附力无关,但与理论液压与净吸力成反比;(4)在界面压力作用下,净吸力在冻融过程中始终保持:P_(Suhi,1)<P_(Suhi,2)<P_(Suhi,3),从而驱动未冻水从微孔→次级孔→主干孔迁移、聚集并相变。总之,界面效应是产生冻融回滞和冻融水分迁移的主要原因。In order to elucidate the phenomenon of freeze-thaw hysteresis and uneven frost heave in soil/rock mass during the freeze-thaw process,the mechanism of freeze-thaw hysteresis and freeze-thaw water migration was studied.Firstly,according to the generalized Clapeyron equation and Gibbs-Thomson equation,the freezing temperature equation of liquid water at any curved interface is given,and the freezing and thawing model of capillary is constructed.Based on this,by introducing the“main-branch type”pore structure with poor freeze resistance,the freeze-thaw hysteresis triangle model of capillary-film water is constructed.Finally,the correctness of the model is verified by low-field nuclear magnetic resonance experiments.The research shows that:(1)due to the difference in the curvature of the freeze-thaw boundary,the capillary pressure is twice the interface pressure,resulting in the melting temperature being only 1/2 of the freezing temperature;(2)the interface pressure is only related to the boundary conditions and has nothing to do with the freeze-thaw process.(3)The interface pressure has nothing to do with the theoretical ice pressure,theoretical suction,migration driving force and surface adsorption force,but is inversely proportional to the theoretical liquid pressure and the net suction;(4)Under the action of the interface pressure,the net suction is always maintained during the freezing and thawing process:PSuhi,1<PSuhi,2<PSuhi,3,thereby driving the migration,aggregation and phase transition of unfrozen water from micropores→secondary pores→main pores.In conclusion,the interface effect is the main cause of freeze-thaw hysteresis and freeze-thaw moisture migration.

关 键 词：土力学 冻融回滞 冻融水分迁移 毛细压力 界面压力 界面效应 

分 类 号：TU43[建筑科学—岩土工程]