【作者】 韩利民；

【导师】 张鲁新；

【作者基本信息】 北京交通大学 ， 道路与铁道工程， 2009， 博士

【摘要】 青藏铁路唐古拉山区由于线路纵向坡度设计控制和不同工程结构过渡衔接的要求,导致冻土路堤结构出现低于冻土区合理设计高度的填土路堤;在采用片石层气冷结构路基时,由于片石层厚度和覆盖土层厚度的局限,有可能出现低于4米的填土路堤。受区域气候条件和水热环境条件影响,上述两类低路堤热学稳定性(保护多年冻土效果)和工程稳定特点有其特殊性。本文从唐古拉山区特殊的区域环境和冻土条件的分析研究入手,通过工程实体试验在建设期及运营期间的观测和长期预测,对影响这类低路堤工程稳定性的热稳定性进行了深入系统的研究。通过对唐古拉山区路基土体冻融过程特点的观测试验研究,分析了填土低路堤结构对基底多年冻土的保护效果,以区域观测数据为计算基础,从理论上计算分析了在环境温度逐年升高和路堤周围水热环境复杂变化下的长期变化趋势。对唐古拉山区几种典型区域环境气候条件的填土低路堤结构实体观测和理论计算得到以下结论:1、在环境气温较低(-5.6℃)的低温冻土区,较长时间段对多年冻土有一定保护作用,但是考虑气温升高的背景,保护冻土作用逐年削弱,必须采取一定工程补强进行预防性整治。2、在环境气温较高(-3.5℃左右)时,无论是低温冻土区还是高温冻土区,对多年冻土都没有明显的保护作用,在气温升高条件下这种低路堤结构必须采取工程补强才能起到保护冻土的效果。从青藏铁路建设和初期运营过程的工程实践和理论计算证明,采用原有土护道+坡脚热棒和片石护道+热棒复合工程结构进行工程补强和预防性整治为保护多年冻土的可靠适宜的工程措施。更多还原

【Abstract】 In order to satisfy requirements of design of longitudinal degree of slope and the joints of different structures,low-roadbed which is lower than critical height was applied in permafrost roadbed constructions in Tanggulashan Mount sector of Qinghai-Tibet railway.The height of embankment is lower than 4m due to the confinements of thickness of rubble and filling when the measure of ballast ventilation is applied.It is some special performances in thermal and engineering stability for above two different low embankments because of the influences of climatic conditions and hydro-thermal environment.Based on analysis of regional environment and permafrost conditions of Tanggulashan Mount region and the survey of test construction and the long-period forecasting,engineering stability of low-roadbed was researched profoundly and systematically in this paper.Effect of protection for substratum permafrost from low embankment is analyzed through studying on the field information about freezing and thawing process in Tanggulashan Mount area.Based on the test data,the tendency of ground temperature is simulated in the theory derivation on the condition of gradual rising temperature and complexity of hydro-thermal environment.After theory derivation and field investigation several lower embankments in different multi-conditionsThe conclusions are as followed:1.In low temperature permafrost region where environmental atmospheric temperature is lower than -5.6℃,low-roadbed construction can protect permafrost effectively in a relative long period.But its effect will be weakened annually when atmospheric temperature is increasing annually,so preventive strengthening measures must be taken.2.when environmental temperature is relative high(about -4℃),the protection effect of low-roadbed construction to permafrost is not obvious,no matter in low temperature permafrost region or in high temperature permafrost region.It must be strengthened.It is effective to apply some preventive strengthening measures such as using soil berm and thermal rods at toe or using foliated rock berm and thermal rods.It is testified by the railway construction and initial operation. ##本文无英文摘要内容更多还原