【作者】 资建民；

【导师】 张海龙；

【作者基本信息】 华中科技大学 ， 结构工程， 2008， 博士

【摘要】 高填方路基相对一般路基而言,具有填筑高度大,填筑断面面积大,路堤本身累积沉降大,稳定性需进行专门分析和验证等特点。在公路工程中高路堤一般是最受重视的分项工程之一,路基沉降,特别是不均匀沉降,导致路面开裂、沉陷,严重影响道路的行驶质量及使用寿命。有效减小路基沉降,消除其所带来的危害是公路建设科技领域的一个重要课题,其研究意义重大。基于我国目前道路建设现状和工程实际问题,本文结合湖北省科学技术厅科技攻关项目,“特殊荷载作用下高填路堤的沉降分析及其控制的数字仿真研究”(编号:2004AA101C92),针对空军某机场道路对路基的特殊要求,进行高填方路基的快速施工技术及沉降计算与分析方法研究。(1)常用的公路软弱地基方法种类繁多,效果、适用范围、经济性等也各有差异。在对各种公路软弱地基处理方法进行分析比较的基础上,针对所研究工程的特殊情况,比选出施工方便、技术可靠、经济快速的软弱地基处理方案。(2)对不同路堤填筑方式所能达到的路堤填筑压实质量进行研究,优化推荐合理的高填方路基快速填筑施工技术方案。根据有限元分析结果确定了合适的路堤填筑压实标准。针对本文所研究的特定条件,提出了最佳分层填筑厚度的概念。(3)采用动力有限元法分析振碾冲压处理对减少路堤不均匀沉降的作用;分析论证冲击压实的有效处理深度和对路基沉降及压实度的影响,对含有复杂地质条件的特殊路段进行分析,用有限元强度折减法分析边坡的稳定性,并验证处理方案的合理性,为路基的合理优化设计与施工提供依据。(4)从岩土材料的弹塑性特征、路堤填料的压实特性和地基土表面附加应力的变化规律等方面对高填方路基的特征进行分析研究。从沉降观测数据和数值模拟计算结果及自重变形等方面,对特殊荷载下快速施工的高填方路基进行沉降过程分析。(5)建立并实施沉降变形观测体系,对软基上的高填方路堤在快速施工及承受特殊施工荷载过程中的沉降发生、发展及变化情况进行跟踪观测,总结分析该段路堤的沉降变形规律及差异沉降情况,为我国道路建设高速发展期间的大量类似工程积累宝贵的原始数据和有益的工程实践经验。(6)应用灰色理论对高填方路基后期沉降进行较准确的预测分析,根据道路工程的特点,在等间隔GM(1.1)模型基础上,建立改进的非等间隔GM(1.1)模型,编制相应计算程序(附录3)。使用该改进的非等间隔GM(1.1)模型对高填方路基沉降进行预测计算,所得预测结果与实际情况相当一致,证明该改进GM(1.1)预测模型,完全满足工程实际需要;误差校验表明本次建模精度检验合格,且精度高于等间隔GM(1.1)模型。更多还原

【Abstract】 Compared with general roadbed, high backfill subgrade has the characteristics such as higher height, larger cumulate settlement and it’s stability should be technical analysed. High backfill subgrade is one of the most important project in highway engineering.The roadbed settlement in highway construction, especially the differential settlements, may lead to the cleft and stagger of pavement, and largely affect the quality of driving as well as the operational life span. So how to reduce the settlement and get rid of the danger made by the settlement has been an important subject in highway construction field and the research has important reality significance.According to the highway construction condition and actual engineering problem, fast construction techniques and settlement calculate as well as analysis method of high backfill subgrade are studied based on a airdrome road.(1) There are many methods to reinforce soft ground. Different Subgrade treatment approaches have different effects and scope of application which also vary in the economic. Based on the analysis and comparison of various treatment methods for highway soft ground s, convenient construction and reliable technology and rapid economic weak foundation treatment programs are elected aimed at project’s exceptional circumstance.(2) Compaction quality of different ways to fill the embankment is studied and the reasonable rapid filling construction technology programs of high roadbed are recommended. The optimum fill standard and fill thickness are confirm by the result of finite element method analysis.(3) Dynamic finite element method is used to analysis the role of crushed stamping method played in reducing differential settlement of the embankment.The efficiency treat depth and the influence of settlement and fill are demonstrated. Finite element strength reduction method is used to analyze slope stability for special sections of complicated geological condition and reasonableness of the treatment program is also verified.(4) The characteristics of high backfill subgrade are studied through elasticity-plasticity character of the rock and soil material, compressed character of the subgrade material and rules of the foundation soils surface stress. The settlement process of special load is analysed from observed dates and the results of digital simulation compute to the deformation by self-resepect.(5) Settlement deformation observation system is established and implemented and settlement occurring and changes of the soft-high filled embankment in the process of fast construction and bearing a special working load are made by tracking observations and conditions of the deformation of the settlement and different settlements of the subgrade are concluded and analyzed, which accumulate large amounts of valuable original data and useful practical experiences in engineering during the development period of China’s high-speed road construction.(6) Fairly accurate prediction and analysis of late settlement of high filled subgrade are made through the application of the theory of gray system. Taking into the account of non-spacing factors of the special nature of road construction and the observation of embankment settlement, improved non - interval GM (1.1) model is established based on the interval GM (1.1) model and corresponding computer program is also established (see Appendix 2). To predict high filled subgrade settlement by using the improved non-spacing GM (1.1) model, the forecasting results consistent with actual situation which verifies that the improved GM (1.1) prediction model can fully meet actual needs. Check error also shows that the modeling accuracy is qualified and the precision is higher than normal GM (1.1) model.更多还原