土体渗流力加载方法实现与应用研究

发布时间：2018-04-25 14:24

本文选题：渗流力 + ABAQUS子程序　；参考：《武汉理工大学》2015年硕士论文

【摘要】：在岩土工程领域中,土体中的水对土体结构性能有很大的影响,其中由土中水压力产生的渗流力问题,是岩土工程领域的一个重要课题。对渗流问题的求解,传统的解析法对复杂边界条件下渗流力场的求解是件很困难的事,而实验法耗费的时间长,资金大,且一般只能做缩尺实验。近年来,数值模拟的方法越来越广泛地应用于求解土体渗流问题当中。ABAQUS有限元分析软件由于其强大的非线性求解能力,在岩土工程中有着广泛的应用,该软件能够很好地模拟土体饱和-非饱和、稳定-非稳定渗流问题以及土体固结变形问题,但是在渗流力问题的处理上存在不足。通过运用该软件的子程序二次开发功能,以实现在土体结构中的渗流力加载。本文以解决用有限元软件模拟实际工程中渗流力的问题为出发点,以渗流力的基本理论为基础,编制ABAQUS的URDFIL子程序命令,实现将渗流分析中得到的各网格单元的孔压值转换为各网格单元的平均渗流力值。渗流力基本概念[1]指在某路径的沿程方向单位体积内土颗粒受到的渗流作用力,本文中水平方向上渗流力即为孔压沿水平方向的梯度值,在重力方向渗流力上,除了沿重力方向的孔压梯度值,还考虑了单位体积内孔隙水重力的作用。在得到各网格单元水平及竖向的渗流力值后,应用DLOAD子程序将渗流力值加载于力学计算模型中对应的单元,实现渗流力在有限元模拟中的加载。通过建立一个简单的一维渗流模型,根据其加载渗流力后的力学变形结果,证明该方法加载的渗流值与理论值相同;再建立另一简单的二维渗流模型,对比渗流加载方式的不同对计算结果的影响,证明当采用面荷载代替渗流力时,得到的计算结果位移偏大,应力的分布更不均匀;最后将该方法应用于东湖通道围堰降水过程的数值计算中,对渗流力场的结果以及力学变形结果进行了分析,得到了降水过程中渗流力分布的一般规律,进一步证明了本文中提出的渗流力加载方法的有效性及准确性。
[Abstract]:In the field of geotechnical engineering, water in soil has a great influence on the structure and performance of soil, and the seepage force caused by water pressure in soil is an important subject in geotechnical engineering. The traditional analytical method is very difficult to solve the seepage force field under complex boundary conditions, but the experimental method takes a long time and has a large amount of money, and it can only be used in scale experiments. In recent years, the numerical simulation method is more and more widely used in solving soil seepage problem. Abaqus finite element analysis software has been widely used in geotechnical engineering because of its strong nonlinear ability. The software can well simulate the saturated-unsaturated, stable-unstable seepage problems and soil consolidation and deformation problems, but there are some shortcomings in the treatment of seepage force problems. By using the secondary development function of the subroutine of the software, the seepage force loading in the soil structure can be realized. In order to solve the problem of simulating seepage force in practical engineering with finite element software and based on the basic theory of seepage force, the URDFIL subroutine command of ABAQUS is compiled in this paper. The pore pressure of each mesh element can be converted into the average seepage force value of each mesh element in seepage analysis. The basic concept of seepage force [1] refers to the seepage force acting on soil particles in the unit volume along a certain path. In this paper, the seepage force in the horizontal direction is the gradient value of the pore pressure along the horizontal direction and the seepage force in the gravity direction. In addition to the pore pressure gradient along the gravity direction, the effect of pore water gravity per unit volume is considered. After the horizontal and vertical seepage force values of each mesh element are obtained, the seepage force value is loaded into the corresponding element in the mechanical calculation model by DLOAD subroutine to realize the seepage force loading in the finite element simulation. By establishing a simple one-dimensional seepage model, according to the results of mechanical deformation after loading seepage force, it is proved that the seepage value loaded by this method is the same as the theoretical value, and another simple two-dimensional seepage model is established. Compared with the influence of different seepage loading modes on the calculation results, it is proved that when the seepage force is replaced by the surface load, the displacement of the calculated results is larger and the stress distribution is more uneven. Finally, the method is applied to the numerical calculation of the dewatering process in the cofferdam of the East Lake Channel. The results of the seepage force field and the mechanical deformation are analyzed, and the general law of the seepage force distribution in the process of precipitation is obtained. The validity and accuracy of the seepage force loading method proposed in this paper are further proved.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43

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