基坑工程是一个古老的课题，但是随着基坑深度的发展及其与周围建筑密度的增加，传统的方法已不再适合于基坑的发展，为此人们提出了变形控制设计概念。变形控制概念的提出，需要相应的数值分析方法来计算各步施工的变形，有限元法以其原理简单以及能够模拟不同土体与支护结构单元、复杂边界条件和多步的施工过程的优势，在众多数值方法中脱颖而出。但是，有限元模拟基坑工程，尤其是对多步施工的基坑工程的模拟，产生了“海量”数据。对“海量”数据的可视化处理，能够使我们更直观地对基坑工程进行分析；对多步施工结果的逼真地动态可视化模拟，可以使对施工产生的影响的了解更加深入。而这一切，都需要一个适用的、可靠的动态可视化模拟程序。 为此，本文首先系统分析了有限元在深基坑模拟计算中的原理。在此基础上，研究了针对二维弹塑性有限元的动态可视化后处理软件AFTERDRAW，AFTERDRAW能够绘制基坑工程各步施工的结构变形图、塑性区和受拉破坏区分布图、主应力矢量图和位移矢量图，AFTERDRAW还能够逼真地动态模拟基坑工程整个施工过程变形情况。最后，本文利用NCAP－2D与AFTERDRAW对北京一深基坑工程进行了动态模拟，并对结果进行了深入分析，认为NCAP－2D和AFTERDRAW对深基坑工程的分析是可信的。 文末，提出了动态可视化模拟中存在的几个问题，及在今后研究中继续努力的方向。

Excavation engineering is an ancient subject. But with the increase of the depth of excavation and density of surrounding constructions, the traditional method has not been suited to the development of excavation engineering. So the concept of deformation control design has been represented. With the appearance of this concept, the corresponding numerical analysis method to compute the deformation in the constructing is quite required in calculation. Since FEM(finite element method) is one kind of simple theory, which can simulate different clay and retrain structure, the complicated boundary condition , and the process of multistep construction, it has been applied in many fields. But a great number of data will be created in the process of simulation, especially in the multistep excavation simulated by FEM. The excavation engineering could be more intuitively analyzed if the data is visualized, and the multistep construction will be learned more deeply when the result of multistep excavation is dynamically visually simulated. So an applicable and reliable dynamic visualization software is in great need. In this thesis, the theory of simulation for excavation by FEM is analysed. Then a dynamic visualization software---AFTERDRAW, which aims at 2D elastic-plastic FEM, is programmed. AFTERDRAW is capable of drawing the deformation figures of material, the regions of plasticity and the regions of tension distributing figures, primary stress vector figures and primary strain vector figures. Besides, ATTERDRAW could realistically dynamically simulate the deformation of the whole process of construction. Finally, a excavation project in Beijing was simulated by NCAP-2D and AFTERDRAW and the result is credible by deeply analyzing. At the end of the thesis, several questions about dynamic visualization simulation and the direction of later study have been put out.