【作者】 张波；

【导师】 陈晓平； 崔红军；

【作者基本信息】 武汉大学 ， 岩土工程， 2004， 硕士

【摘要】 软土在我国分布较广，跟软土相关的工程建设项目很多，软土的工程性质差，孔隙比大、含水量高、强度低。在工程建设中，软土地基承载力低，易于变形，难以满足工程需求，必须进行加固处理。因此，我们必须对软土的性质进行深一步的研究，而软土的固结对土的工程性状有着重要的影响，与土工建筑物和地基的渗流、稳定及沉降等问题有密切联系，在研究软土固结的同时必须考虑软土的流变性质。 软土的蠕变是指外力作用后变形随时间增长的现象，固结是指外力作用后土体骨架中超静孔隙水压力消散的过程。在土力学中，固结理论和流变理论是从各自不同的角度反映土体变形的客观规律，两种理论通过变形机理联系在一起。 本文首先介绍了软土的工程性质及其本构模型，然后介绍了土的固结理论和流变理论的研究概况以及数值方法在岩土工程的应用情况。接着具体介绍土的固结理论及其求解方法，详细叙述土的流变模型及本构方程。在此基础上提出了软土蠕变-固结模型，建立本构方程，推导了非线性弹粘性固结问题的有限元方程。本文还对深圳海淤土做了蠕变试验，从中可以看出软土蠕变的基本规律，软土瞬时变形呈现明显的非线性，软土蠕变变形和超静孔压的消散有关，它对应力和应变的影响取决于土体的排水条件，排水条件不良时，蠕变影响大。本文在TDBC-95程序基础上运用FORTRAN语言编写比奥固结有限元程序，对武山铜矿1号尾矿坝地基固结沉降问题进行分析，计算结果和实测资料进行比较，验证本程序的可行性与正确性，同时通过计算模拟施工过程，可以作为类似工程施工进程的参考，为实际问题提出解决施工控制。更多还原

【Abstract】 Soft soil is in existence all over the country. A lot of engineering items’have relations with soft soil. Its engineering characteristic is bad with bigger void ratio, higher water content, lower intensity. In engineering constructing, we have to reinforce the soft ground because of its lower carrying capacity and aptness to deform. So we must make a deeper research for the property of soft soil. The consolidation of soft soil influences greatly on engineering characteristic of soil, and has close relation with such problems as filtration stability, subsidence etc of earth structure and foundation. And we should think over rheologic properties when we study the consolidation of soft soil.Creep of soft soil means that deformation is rising with time under certain outside force. Consolidation is the course of super pore-pressure dissipation after loading. In Soil Mechanics, consolidation theory and rheologic theory reflect the external orderliness of soil displacement in different way. These two theories are contacted with each other by deformation mechanism.In this paper the engineering characteristic and Strain-Stress model of soft soil are presented. Then the general research situation of consolidation theory and rheologic theory are elaborated systematically, the application of numerical measures is introduced. In this paper the consolidation theory and its solution ways of soil are detailedly narrated. The rheologic model and Stress-Strain equation of soil are also recounted. On base of these, a creep-consolidation model of soft soil is brought forward, the Stress-Strain equation is also founded. The lunited element equation of nonlinear elastic-viscous consolidation model is constructed. An indoor experimentation about creep deformation of Shenzhen ocean silt soil was done. General creep deformation characteristics are derived. Test shows that the instantaneous displacement presents obvious nonlinear property, and the creep deformation of soil is related to pore-pressure dissipation. The influence of creep on stress and strain is decided by drainage condition of soft foundation. The influence will aggrandize when drainage condition is bad. Based on TDBC-95 program, awill aggrandize when drainage condition is bad. Based on TDBC-95 program, a Biot consolidation finite element program is compiled by Fortran language. The program is used to calculate the consolidation subsidence. Compared with the observational datum, the program is proved to be feasible and exactitude. It also can be used to simulate the constructing process, to offer referrence for analogous engineering and to supply project for constructing.更多还原