公路软土地基处理的沉降分析研究

发布时间：2018-12-11 09:58

【摘要】：修建高速公路过程中，常遇见工程地质条件不良的软土地带，此地带具有沉降量大、压缩性高、排水固结稳定性差的特点。软土地基处理的关键是控制处理过程的沉降速率与最终沉降量在设计要求内，本文主要研究沉降量的理论计算方法和FLAC3D数值分析模型拟合实际沉降过程。首先对软土的定义、物理特性、分类、软土地基主要需解决的问题四个方面展开叙述。接下来对公路地基不同处理方法的原理、适用范围、优点及局限性进行了详细的介绍。通过荆东高速公路实例，对合同段的软土层分析、处理方案的选择与优化、沉降观测等进行了详述；典型断面的沉降观测数据，为后面沉降预测方法的研究提供数据基础。在公路软基处理中，沉降预测是必不可少的，在路堤施工期间，为及时掌握其变形的动态，动态观测与建立软基沉降动态预报系统是必不可少。文中先对双曲线法、泊松曲线、Asaoka法、指数曲线法和皮尔曲线法等沉降预测方法从理论上进行详述，然后分别用双曲线法、三点法、Asaoka法三种方法来理论计算实例的沉降量，再用每种方法的结果与实际最终沉降量进行误差分析，得出合适的预测方法。 FLAC3D是一款适用于连续介质力学分析的软件，该程序处理复杂力学问题的能力强大。通过FLAC3D建模对荆东高速公路软基超载预压下的沉降进行分析，以验证其前预测方法，结果与实际情况拟合很好。最后可以得出结论，FLAC3D数值计算方法适合于模拟预测超载预压条件下软土地基的沉降变形。
[Abstract]:In the process of highway construction, soft soil with poor engineering geological conditions is often encountered, which is characterized by large settlement, high compressibility and poor stability of drainage consolidation. The key of soft soil foundation treatment is to control the settlement rate and final settlement within the design requirements. This paper mainly studies the theoretical calculation method of settlement and the FLAC3D numerical analysis model to fit the actual settlement process. Firstly, the definition, physical properties, classification and main problems of soft soil foundation are described. Then the principle, application range, advantages and limitations of different treatment methods of highway foundation are introduced in detail. Through the example of Jingdong Expressway, the soft soil layer of contract section is analyzed, the selection and optimization of treatment scheme, settlement observation and so on are described in detail, and the settlement observation data of typical section provide the data basis for the research of settlement prediction method in the future. During the construction of embankment, dynamic observation and establishment of dynamic forecasting system of soft foundation settlement are essential in order to grasp the deformation dynamics in time. In this paper, the settlement prediction methods such as hyperbolic method, Poisson curve, Asaoka method, exponential curve method and Pier curve method are described in detail in theory, and then the settlement of an example is calculated theoretically by using hyperbolic method, three-point method and Asaoka method, respectively. Then the error analysis between the results of each method and the actual final settlement is carried out, and the appropriate prediction method is obtained. FLAC3D is a software for continuum mechanics analysis, which has a powerful ability to deal with complex mechanical problems. The settlement of the soft foundation of Jingdong Expressway under overload preloading was analyzed by FLAC3D model to verify the pre-prediction method. The result fits well with the actual situation. Finally, it can be concluded that the FLAC3D numerical method is suitable for simulating the settlement and deformation of soft soil foundation under overload preloading.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.16

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