【作者】 黄明奎；

【导师】 汪稔；

【作者基本信息】 中国科学院研究生院（武汉岩土力学研究所） ， 岩土工程， 2005， 博士

【摘要】 以中国科学院重大知识创新工程《青藏铁路工程与多年冻土相互作用及其环境效应》为依托,在总结了前人沿用的各类保护冻土措施的基础上,分析并研究了一种应对全球气候变暖的积极主动保护冻土的新型的路基结构形式——粒径改良路基。它主要是通过路基填土颗粒的筛分、颗粒重组,从而改变路基填土的结构来改变路基与大气之间的热交换关系,最终达到保护冻土的目的。首先通过现场试验,从温控效果及变形两方面,对粒径改良路基温控机理进行了研究分析;其次以多孔介质为媒介,分析探索了粒径改良路基的热物理参数,从而分析其在多年冻土区的温控机理。主要结论包括以下几个方面:1、总结分析了前人沿用的各类保护冻土的措施,指出其适用范围及不足,针对目前全球气候的变暖以及多年冻土逐渐退化的现状,认为充分利用青藏高原本身的自然气候条件,研究开发新的温控措施,是多年冻土区工程冻土保护研究发展的一个重要方向。2、详细分析了粒径改良路基在冻融循环过程中地温变化规律及热状态变化规律,并同其他处理措施及天然场地进行了对比分析,认为:粒径改良路基具有冷量交换和热量屏蔽的热二极管效应,是一种有效的保护冻土的措施。3、对新研制开发的变形监测系统——光纤多点应变仪进行了可靠性验证,表明:该系统在冻土区变形测量中具有较好的可靠性,测试精度满足科研、工程实际要求。4、对粒径改良路基进行了变形性能研究。结果表明:粒径改良路基在一定程度上缩短了路基冻结时间,减缓了冻胀变形。在稳定性方面,无论从冻土上限还是单向变形考虑,粒径改良路基均为一种稳定的路基结构形式。5、从粒径改良路基设计参数出发,详细分析了粒径改良路基所应满足的厚度,并提出:在一般粗颗粒填料活动层范围内,可以不考虑未冻水对热对流所产生的影响。6、根据流体在多孔介质中流动的毛细模型,对粒径改良路基热参数进行了探索与分析。认为:在多年冻土区,应综合考虑当地自身的气候条件,以保护冻土为目的,合理选择粒径改良土的颗粒直径、厚度及孔隙度。7、详细分析了粒径改良路基冻结、融化深度计算方法,根据传热学多层物质热阻的串连原理,通过导热等效的原则,对多层粒径改良路基计算原理进行了简要分析。更多还原

【Abstract】 With the significant initiative project of Qinghai-Tibet Railway Project and Interaction & Surroundings Influences by Permafrost by Chinese Academy of Science as background, in this dissertation a general summary of the various measures for frozen soil protection by the previous researchers has been made, with the presentation of the research achievements of the new-typed roadbed structures– the particle improved roadbed, aiming to protect the frozen soil against the globe-warming influences in an active way. It is mainly through the filtering and restructuring of the bedroad-filling granules to change the original structure of the roadbed, thus to change the heat-exchange relationship of the roadbed and the atmosphere with the protecion of the frozen soil as the eventual purpose. Firstly it is through the spot experiment to conduct research into the particle improved roadbed temperature control mechanism with observation on both temperature control effect and deformation. Secondly, in order to analyse the temperature control mechanism of the particle improved roadbed in permafrost region, the thermal parameters are searched in the presence of the porous medium. The main achievements include the following parts:1、The various measures to protect frozen soil by the previous researchers are summarized and the applicable range and the deficiency of those are expouonded. Based on the present situation of globe-warming and the status quo of the gradual degeneration of the frozen soil, the new-typed temperature control measure to protect frozen soil in permafrost has been develped making advantage of the natural climate conditions of the Qinghai-Tibet plateau,which is an essential direction of the research in permafrost regions.2、The rules of particle improved roadbed’s thermal state change and the ground temperature change in the cycle process of freezing and thawing are analysed in detail, and comparation with natural spots as well as other processing measures is made in the meantime,drawing the conclusion that the particle improved roadbed, able to function as a diode to make a change of the coldness and resist the heat, is an effective measure to protect frozen soil.3、It also conducted a validation to the reliability of the newly developed deformation monitoring system—photic fiber multipoint momitor.The result shows that this system has a high reliability in the measuring of the deformation in permafrost, and the testing accuracy can meet the demands of scientific research and specific project.更多还原