【作者】 严学斌；

【导师】 许兆义；

【作者基本信息】 北京交通大学 ， 道路与铁道工程， 2013， 博士

【摘要】 青藏铁路冻土环境特征和未来气温升高趋势决定了冻土路基工程设计必须以“冷却地基”为主导思想,采取能够降低路基基底土体温度,保护多年冻土的特殊路基工程结构和综合性工程措施。·但是未来气温升高和冻土环境变化的不确定性对冻土区路基工程的长期稳定性有很大影响,如何评价运营以后的冻土区路基工程稳定性是青藏铁路运营养护工作的重要课题。本文以青藏铁路五道梁低温冻土区不同结构形式断面的冻土地温变化实测数据为基础,进行了不同冻土路基结构形式长期稳定性评价方法的研究。主要研究内容如下：1、为进行冻土路基稳定性评价研究,建立了青藏铁路五道梁低温冻土区冻土地温观测系统。2、对经过冻融循环的五道梁冻土区路基、桥涵等特殊结构形式断面的冻土地温测试数据的时空变化规律进行了分析。3、在五道梁地温变化规律的基础上,研究了影响冻土地区稳定性的主要因素,进而考虑各种因素的影响,构建了模糊综合评价的理论模型,对青藏铁路沿线不同地段的冻土路基稳定性进行了评价。在此基础上,建立了模糊推理评价模型,对五道梁区域的路基稳定性进行了评价。4、基于人工神经网络技术建立了冻土地温与沉降变形的映射关系模型,对片石路基的稳定性进行了分析。总之,论文是以青藏铁路五道梁地段的冻土工程实践为基础,从宏观、中观、微观角度研究了冻土区路基稳定性的影响因素,基于模糊数学、人工神经网络的评价方法组合应用构建评价模型,提出了相应的青藏铁路冻土区路基的稳定性评价方法。研究成果应用于青藏铁路运营后的维修养护工作,不仅对青藏铁路路基病害的预警有直接的作用,对今后类似工程建设也有重要的指导意义。更多还原

【Abstract】 The special permafrost environmental characteristics and climate warming tendency in future decided the cooling subgrade idea should be adopted during Qinghai-Tibet railway subgrade design. Many comprehensive measures of degrading the ground temperature at bottom of embankment should be used to protect permafrost under subgrade. As many unsure factors relating to climate warming and permafrost environment changing could affect the long-term stability of subgrade greatly. How to evaluate the subgrade stability after the railway being in use was the most important item for Qinghai-Tibet maintenance.By means of ground temperature data from different types of permafrost structure section in low temperature area, wudaoliang, the long term stability evaluation method was studied for different style of subgrade structure. The paper include,To carry out the study on stability evaluation for permafrost subgrade, the ground temperature monitoring system was build in wudaoliang area of the low temperature permafrost region.The ground temperature data variation with time and depth from subgrade, bridge and culvert basement experiment were arranged and analyzed depending on the different section of the long term monitoring in Wudaoliang permafrost area.The paper studied the main effect and control factors of permafrost subgrade stability. Considering these factors, the theoretical fuzzy comprehensive modal was built. With this method, the different area of permafrost subgrade stability was evaluated for Qinghai-Tibet railway. Furthermore, the fuzzy inference rule modal was established to evaluate the test sections stability in Wudaoliang area.According to artificial neutral network, the ground temperature and settlement mapping relation modal were deduced to evaluate the permafrost subgrade stability of embankment with riprap in high temperature and fine soil area of Qinghai-Tibet railway.In general, in response to the permafrost engineering practice, the paper studied the effect factors for subgrade stability in Wudaoliang area of Qinghai-Tibet railway. Based on fuzzy mathematics, artificial neural network evaluation built-up modal, the corresponding stability evaluation methods for Qinghai-Tibet permafrost subgrade were presented. The results would affect directly for subgrade disease control and the railway prewarning, furthermore, it would guide the similar engineering construction well for future.更多还原