【作者】 郝占刚；

【导师】 朱平； 刘欣；

【作者基本信息】 天津大学 ， 水利工程， 2009， 硕士

【摘要】 天津港广范分布有工程性状较差,新近吹填形成的具有很高的含水量和很低强度的淤泥性质粘土。真空预压法作为排水固结法的一种,近年在天津港软基加固中得到了广泛地应用,取得了很好的经济效益和社会效益。本文在回顾总结真空预压技术的发展历史和研究现状基础上,通过理论分析和现场试验,以天津港实际工程为背景,对真空预压在软基加固方面的应用进行了探讨和研究。详细阐述了真空预压法加固机理,根据现场试验,论述了真空预压的现场施工步骤,对真空预压期间的膜下真空度、地表沉降、分层沉降、孔隙水压力以及侧向位移等监测项目结果进行分析,对加固前后的土层物理力学指标和原位十字板抗剪强度进行对比。应用有限元软件Plaxis进行实际工程的模拟计算及分析,采用平面应变模型和莫尔-库仑土体本构关系,模拟真空预压中孔隙水压力的变化和真空预压下土体的固结变形过程。模拟过程中,采用了真空荷载法进行加荷计算,所得结果与真空预压工程实际吻合较好。更多还原

【Abstract】 The new formed silt clay with high moisture content and low strength is widely distributed in Tianjin Port. The vacuum preloading method which is one kind of drainage consolidation methods has been widely used in the soft foundation reinforcement in Tianjin Port recently. It has achieved good economic and social benefits.On the basis of the developing history and current research condition of vacuum preloading, as well as in combination with the project sample study of Tianjin Port. The thesis carries through the following research word aiming at the application and research of vacuum preloading on the shallow soft ground consolidation based on theoretical analysis and on-site testing.The mechanism of vacuum preloading was discussed by contrast of vacuum preloading and heaped preloading. The vacuum preloading consolidation theory has been discussed. Based on the field test, the construction steps of vacuum preloading have been gained. And the results of vacuum degree under the membrane, layer settlement, delamination settlement, pore pressure and lateral displacement in the process of vacuum preloading have been carried out. The physical and mechanical indexes of soft soil were discussed by contrast of vane shearing strength before and after the consolidation.The software named Plaxis is used to make some numerical analysis in the practical engineering, in which the Mohr-Coulomb model was adopted. In the analysis, the vacuum loading is applied. The results indicate that it is closed to the tests in situ.更多还原