【作者】 汪双杰；

【导师】 黄晓明；

【作者基本信息】 东南大学 ， 道路与铁道工程， 2005， 博士

【摘要】 为研究青藏公路冻土病害处治对策,从青藏公路2002年～2004年冻土病害整治工程实际出发,在系统分析研究青藏公路病害及发生机理的基础上,运用室内模拟试验、数值分析方法,依托处治冻土病害路段实际使用的隔热板路基、碎石路基、无动力热棒路基等进行现场试验,分析边界温度周期波动条件下的路基温度场分布规律,同时进行一般路基不同边坡坡率的对比研究及有无护坡道的对比研究;运用数值分析方法,对气温升高趋势下隔热板、碎石、无动力热棒的隔热降温效果进行了研究;选择代表性路段观测资料,运用数值计算的方法,进行升温趋势下的路基变形预测,研究路基融沉变形对路面应力的影响。建立了气候升温背景下沥青路面冻土路基温度场计算模型,提出了路基合理高度与时间关系的数学表达式,提出了保温隔热层合理厚度及等效路基厚度的计算表达式,提出了碎石最佳粒径范围和合理层厚与铺设位置,模拟并验证了热棒的有效工作半径,探讨了以路面层底拉应力控制的路基融沉变形与路基填土高度的关系。研究认为,在全球气候变暖和工程活动的双重作用下,路基下冻土升温而导致的路基病害将是一个长期的过程,工程处治对策只能减缓病害的发展过程并有效控制规模,但难以根本上解决冻土路基的融沉变形问题;保持冻土上限稳定的路基合理高度是随时间变化的;放缓路堤边坡及设置保温护道无助于改善冻土路基的热稳定性;EPS板隔热层适用于低温冻土区;碎石路基是青藏高原合理经济的路基结构形式;无动力热棒路基能降低地温,是解决高温冻土区路基病害的有效措施;路面层底拉应力对路基变形响应敏感,高温冻土区应考虑控制路基最大高度。更多还原

【Abstract】 In order to study on treatment measures of frozen soil distresses of Qinghai-Tibet highway, field experiments on road sections with thermal insulation slab subgrade, broken stone subgrade and non-power heat pipe subgrade in practical treatment of frozen soil distresses were made on the basis of systematical analysis of distresses of Qinghai-Tibet highway and their mechanism and relying on treatment engineering of frost soil distresses in Qinghai-Tibet highway from 2002 to 2004. Based on them, distribution laws of subgrade temperature field under fluctuant boundary temperature cycle conditions are analyzed, and different ratios of slope for general subgrade and different status when there are or not banquettes are compared by laboratory simulation and numerical analysis; thermal insulation and cooling effect of thermal insulation slab, broken stone and non-power heat pipes is respectively investigated under the trend of elevated temperature by numerical analysis, laws of subgrade deformation are predicted under the trend of elevated temperature and influences of subgrade thaw settlement on pavement stress are studies by numerical computation for observation data of representative road sections selected. A model of permafrost subgrade temperature field for asphalt pavement is established under climatic change conditions, mathematical expressions about the relation between reasonable height of subgrade and time are put forward. At the same time computation expressions of the thickness of heat insulation course and of equivalent subgrade height are proposed. The best range of particle size, the reasonable course thickness and installation position of broken stone are advised, effective operating radius is simulated and validated and the relation between subgrade thaw settlement and height of subgrade fill controlled by tension stress of the bottom of pavement layer is discussed. Researches indicate that: under double acting of climate and engineering, subgrade distresses resulting from permafrost warming under subgrade is a long-term developing process so taking engineering treatment measures can alleviate distresses development and effectively control the scale but thaw settlement of permafrost subgrade cannot be radically solved; reasonable subgrade height preserving permafrost table varies with time; reducing angle of subgrade slope and heat insulation berm can contribute little to the improvement; the insulating courses of EPS slabs are suitable for low-temperature regions; broken stone subgrade is economical and rational subgrade structure; non-power probe subgrade which can cool ground temperature is a kind of effective measure to subgrade distresses in high-temperature permafrost regions; tension stress of the bottom of pavement layer is sensitive to subgrade thaw settlement and the biggest subgrade height of subgrade should be considered to be controlled in high-temperature permafrost regions.更多还原