【摘要】 冻融作用是诱发寒区工程构筑物破坏与失稳的主要原因.近十年来,采用室内试验研究冻融作用对土的工程性质的影响取得了长足进步.在分析并归纳现有冻融试验方法的基础上,从冻融作用对土的结构、基本物理参数、工程力学性质等的影响及抗冻融改良措施等方面综述了该领域的研究成果,取得如下主要认识:(1)统一冻融试验方法是系统地分析冻融作用对土的工程性质影响规律的前提,也是建立土体抗冻性能数据库的基础;(2)土的粒径分布、孔隙形态以及初始含水率等三方面因素决定着冻融作用对土结构的影响程度;(3)冻融试验方法和土的初始状态是决定冻融作用对土的物理性质影响程度的主要因素,当土的物理参数处于临界状态值时,相应的物理性质将不受冻融作用影响;(4)冻融循环作用导致土的强度及模量先降低随后趋于稳定,但土的抗剪强度指标的变化规律差异较大,可从试验条件及土的初始状态存在差异等方面查找原因.融化过程中出现的"温度阈值"现象值得引起关注;(5)提高土的抗冻融性能应该从改善土的颗粒级配、孔隙形态以及初始含水率等三方面入手来筛选改性剂及改良方法.更多还原

【Abstract】 Freeze-thaw effects are the main reason that cause damage and instability to engineering structures in cold regions.Laboratory tests for freeze-thaw effects on soil geotechnical properties have made great progress during the past decade.Based on analyzing and summing up current freeze-thaw test methods for soil,the research results in effects of freeze-thaw on the structures,basic physical parameters and mechanical properties of soil and corresponding frost-resistant measures for soil are summarized,the main results shown as followed:(1) an united freeze-thaw test method is the base of analyzing the freeze-thaw effects on soil geotechnical properties and establishing soil database for freeze-thaw properties.(2) Degrees of freeze-thaw effects on soil structure depend on particle size distribution,pore shape and initial moisture content of soil.(3) Freeze-thaw test method and initial state of soil are the main reasons that determine the influence degree of freeze-thaw effects on physical properties of soil,and some physical properties of soil will not be affected by freeze-thaw effects when the corresponding parameters value at a critical state.(4) Strength and modulus of soil decrease with the increasing freeze-thaw cycles at first,and tend to a stable state later.But there are differences in the change rules of freeze-thaw effects on the shear strength parameters because of diversity of test method and initial state of soil.And the phenomenon of temperature threshold during the thawing process of soil should be noted.(5) Methods of mitigating the freeze-thaw effects on soil geotechnical properties should be started by improving the particle size distribution,pore shape,and initial moisture content of soil.更多还原