Study On The Temperature Control Mechanism And The Test Of The Particle Improved Roadbed In Qinghai-Tibet Railway

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.