【作者】 徐军海；

【导师】 高正夏；

【作者基本信息】 河海大学 ， 地质工程， 2004， 硕士

【摘要】 在软土地基上修建高速公路时，面临的主要问题是稳定和变形。由干路堤设计高度一般只有几米，稳定条件较易满足。所以，对于路堤工程，特别是对路面变形的要求非常严格的高速公路路堤工程，软土地基的沉降变形问题成为路堤建设的关键性土工技术问题。高速公路工后沉降的设计要求很高，相应对软土地基沉降的预测分析精度要求也很高，传统的计算方法已经无法满足这一要求。本文从影响路基沉降的不确定性因素出发，做了一些研究工作。 对于重要工程或重要地段的软土沉降反演计算，采用基于模型辨识的参数反演方法。根据模型辨识的原则和路基沉降的特点，把软土沉降计算模型的辨识分为二个层次：介质形态初步模型的辨识和最优模型的辨识。为了考虑软土次固结作用对软土地基后期影响，在传统考虑弹性、非线性弹性模型的模型类属集合中力口入了Merchant粘弹性模型。 对于一般工程的路基沉降计算，采用基于模型辨识的曲线拟合法。并且基于影响路基沉降分析的不确定性荷载因素，对车辆荷载及填土荷载逐级施加两种情况进行了量化分析：依据太沙基固结理论，推导了两种情况下的土层平均固结度公式，由此分析和讨论了不确定性荷载因素影响下路基固结的特性。在考虑填土荷载逐级施加情况的基础上，对指数法进行了改进。 结合徐宿高速公路，进行了基于模型识别的路基沉降反演预测和各类曲线拟合法预测工后沉降的计算，通过计算验证了模型识别反演预测思路和方法的适用性和改进指数法预测路基工后沉降的有效性和合理性。更多还原

【Abstract】 The stability and deformation are the main problems for expressway constructed on the soft soil ground. The requirement of stability is easily reached, due to the design height of embankment is several meter. For embankment engineering of expressway, where the pavement deformation is strictly limited, the settlement of soft soil ground becomes the key engineering technique problem. The precision of the embankment’s settlement forecast and analysis should be higher because the design of the expressway back-work settlement is exactly confined. Therefore, the traditional algorithm method can’t meet the demands. Based on the uncertain factors affecting embankment’s settlement, the paper makes some research work.For important engineering or important embankment, the method of parameter inverse analysis based on model discerning is used to calculate the embankment’s settlement. According to the principle of model discerning and the feature of embankment’s settlement, the calculation model of soft soil ground’s settlement is divided into the material discerning of the first model and the best model, In order to consider the soft soil ground’s settlement affected by the secondly consolidation in the later stage, the Merchant visco-elastic model based on the elastic model and the non-linear-elastic model is adopted.For the ordinary engineering, the curve fitting methods based on model discerning are introduced to calculate the embankment’s settlement. On the basis of the uncertainty load factors which influence embankment’s settlement, the vehicle load and the step-exert construction load are studied by quantity. According to the Terzaghi’s consolidation theory, the average consolidation degree formulas of the corresponding situations are inferred. Moreover, the feature of the embankment’s consolidation in the effect of uncertainty load factors is studied. At the same time, based on analyzing the step-exert construction load, the index method is improved.The inverse analysis method based on model discerning and all these curve fitting methods are used to forecast settlement of Xuzhou-Suqian expressway after completing. The result from calculation and analyzed shows the thinking and the method in the paper are suitable, and it can be proved its rationality and feasibility in studying and forecasting settlement after construction of the embankment.更多还原