冻融作用对土的工程性质影响的研究进展

发布时间：2018-12-24 12:02

【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.
[Abstract]:Freezing and thawing is the main cause of the damage and instability of engineering structures in cold regions. In recent ten years, laboratory tests have been used to study the influence of freeze-thaw on the engineering properties of soil. Based on the analysis and induction of the existing freeze-thaw test methods, the research results in this field are summarized from the aspects of the influence of freeze-thaw action on soil structure, basic physical parameters, engineering mechanical properties and improvement measures against freezing and thawing. The main conclusions are as follows: (1) the unified freeze-thaw test method is the premise of systematically analyzing the influence of freeze-thaw action on the engineering properties of soil, and it is also the basis of establishing the database of soil frost resistance; (2) the influence of freezing and thawing on soil structure is determined by three factors: particle size distribution, pore shape and initial moisture content. (3) the test method of freeze-thaw test and the initial state of soil are the main factors that determine the degree of the influence of freeze-thaw on the physical properties of soil. When the physical parameters of soil are in the critical state, the corresponding physical properties will not be affected by freeze-thaw. (4) the strength and modulus of soil decreased first and then tended to be stable due to freeze-thaw cycle, but the variation law of soil shear strength index was quite different, and the reasons could be found from the experimental conditions and the initial state of soil. The phenomenon of "temperature threshold" in thawing process is worthy of attention. (5) to improve the freeze-thaw resistance of soil, it is necessary to select modifiers and improve methods by improving soil particle gradation, pore morphology and initial moisture content.
【作者单位】：哈尔滨工业大学交通科学与工程学院;辽宁省交通科学研究院有限责任公司;
【基金】：国家自然科学基金项目(批准号:51408163,51578200) 黑龙江省自然科学基金重点项目(批准号:ZD201218) 国家重点基础研究发展计划(编号:2012CB026104)资助
【分类号】：TU445

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