地下水模型中包含非饱和水流对于采用实际的物理分析结果非常重要。在土中，水的传导性和含水量、或者储水量，虽则孔隙水压力成函数变化。SEEP/W采用连续函数模拟这种关系。许多其他渗流分析软件不考虑这些关系。相反，采用理想化的物理假定这些函数是分部函数。比如：当孔隙水压力大于等于0( 如位于水位以下) ，有一个饱和的导水值；当小于0时(如在水位以上), 导水性为0。采用这种理想化的分部函数来模拟导水性和含水量会导致错误的分析结果。
This section gives a few examples of the many kinds of problems that can be modelled using SEEP/W. Highlighted here are problems that require an analysis of flow in both the saturated and unsaturated zone to obtain realistic results and for which models capable of modelling saturated flow only, do not suffice.
本节给出能够采用SEEP/W模拟的诸多问题的部分例子。这里显亮的是一个要求在饱和和非饱和区采用实际结果分析，模型只能模拟饱和水流（不充分）出现的问题

Unconfined Flow
SEEP/W can readily handle unconfined flow problems because it is formulated to compute both saturated and unsaturated flow. With SEEP/W you discretize your entire flow domain into a finite element mesh. After achieving a converged solution, the zero-water pressure contour within the mesh is the phreatic surface, as illustrated in Figure 1.1. The phreatic surface is not a flow boundary, but simply a line of zero pore-water pressure. Not only does this simplify the analyses of unconfined flow, but it includes the flow in the capillary zone above the phreatic surface, which is a real and significant component of the total flow. This portion of the flow is illustrated by the flow vectors above the phreatic surface in Figure 1.1.
Figure 1.1 Unconfined Flow Through an Earth Dam
因为SEEP/W是同时计算饱和和非饱和水流的公式，因此能解决非约束流态问题。采用SEEP/W你划分你的全部水利要素到一个有限单元网格中去， 如图1.1，通过成功获得converged solution，网格中的0水头结果就是浸润线。浸润线不是水面边界，仅仅是一个0水头孔压线。非约束水流的分析不仅如此，而且包括浸润线上部的capillary zone，是整个水流的重要组成部分。这部分的水流通过流线在浸润线上方指示出来。
Precipitation Infiltration
Inclusion of unsaturated flow in the analysis allows you to analyze a wide range of infiltration problems such as the infiltration of precipitation. In these cases, a physically realistic analysis must adequately compute flow through the unsaturated zone as the infiltrating precipitation migrates downward.
Figure 1.2 illustrates a typical case of precipitation infiltration. A less permeable layer in the ground has some profound effects. It creates a perched water table and causes some flow to exit near the top of the slope and some vertical flow throughout the less permeable layer into the underlying slope, ultimately exiting below the slope toe. The shaded areas in the figure are saturated zones while the non-shaded areas are unsaturated zones with negative pore-water pressures. This type of analysis can only be performed by including unsaturated flow in the analysis.
Figure 1.2 Precipitation Infiltration Resulting in Perched, Inverted and Mounded Water Tables
包含非饱和的流程在分析模型中，允许你分析广泛的范围的渗入问题 , 如坠落的渗入。在这些情况，当那个浸润坠落移动的时候 , 一项物理现实的分析必须足够地计算流程经过没有饱和的区域下泄。 图 1.2 举例说明坠落渗入的一个典型的情形。 一个地下弱透水层产生了显著的影响。 它产生一个被栖息的地下水面导致水流从靠近该层坡面顶部渗出和一些垂直的流程顶端的附近进入下面的坡面,最后在坡趾渗出。 图中阴影部分是饱和区，非阴影部分是非饱和区同时有负的孔隙水压力。 这种分析只能通过包括非饱和水流在分析模型中才能解决。

Pond Infiltration
Infiltration of water from surface ponds is another type of infiltration analysis. In these cases the pond water continually enters the ground. However, for certain soil conditions, the soil may not completely saturate the soil below the pond as water flows downward from the pond to the natural water table. Again, computations which include the unsaturated flow are required for the analysis to be physically realistic.
Figure 1.3 illustrates a case where leakage from a pond causes mounding of the natural water table. SEEP/W allows you to model the water table mounding and answer questions such as determining the impact that clay liners can have on the mounding.
Figure 1.3 Pond Infiltration Resulting in Inverted and Mounded Water Table
水池表面的渗透水是另外一种渗流分析，在这种情况下水池水持续的进入地下。然而 ，对于一定的土层条件，池下土层不一定完全饱和因为水流从池中向自然水位下泄。同样，物理实际分析要求包含非饱和水流。

图3 表示从一个水池渗透导致渗漏引起自然地下水位的升高的事例，SEEP/W允许你模拟水位升高，并且回答了比如确定岩层水位升高的影响。
Excess Pore-Water Pressure
SEEP/W can also be used to model the dissipation of excess pore-water pressure. A typical case is the dissipation of pore-water pressure in an embankment after drawdown of a reservoir. Consider the case in Figure 1.4. A steady-state condition may have been reached after some time and then the reservoir is suddenly emptied. SEEP/W’s saturated/unsaturated formulation makes it possible to analyze the dissipation of the excess pore-water pressure. Note the flow out of the embankment in Figure 1.4.
The capability of modelling the dissipation of excess pore-water pressure also makes it possible to perform consolidation analyses. This is discussed later in this chapter in the section entitled Product Integration.
Figure 1.4 Dissipation of Excess Pore-Water Pressure in an Earth Dam After Reservoir Drawdown，
超静孔隙水压力
SEEP/W也能模拟超静孔隙水压力的消散，一个典型的例子就是水库水位降落引起的超静孔隙水压力的消散，图4考虑了这种情况，经过一段时间水位达到了稳定后突然放空，SEEP/W的饱和和非饱和公式使它能够分析超静孔隙水压力的消散，图4示意了堤防水的流出，分析超静孔隙水压力的消散的能力使其能够执行固结分析，题为产品说明部分会在以后章节讨论这个问题。

Transient Seepage
Another large class of problems that can be analyzed using SEEP/W is transient seepage. SEEP/W can account for the drainage of water from soil pores, or water filling soil pores, and the changes in hydraulic conductivity that occur in a transient seepage flow system. Examples of transient analyses are illustrated in Figures 1.5 and 1.6. Figure 1.5 shows the migration of the wetting front through an earth dam after reservoir filling while Figure 1.6 shows the changing position of the phreatic surface after reservoir drawdown.
Figure 1.5 Transient Wetting Front Migration Through an Earth Dam After Reservoir Filling
能用SEEP/W分析的的另一个大类问题就是瞬时渗漏，SEEP/W能够解释水的drainage从土的空隙，或者说水填充图空隙，以及出现在瞬时渗流系统的导水性的变化，再图5、6 中图示了瞬态分析的例子，图5表明了水库充水后湿润前的移民？通过一个土坝，图6 表明水库降水浸润线的位置变化。

均属原创,如有不当,请指正!

User Interface
使用界面
Problem Definition
问题的定义
CAD is an acronym for Computer Aided Drafting. GEO-SLOPE has implemented CAD-like functionality in SEEP/W using the Microsoft Windows graphical user interface. This means that defining your problem on the computer is just like drawing it on paper; the screen becomes your "page" and the mouse becomes your "pen." Once your page size and engineering scale have been specified, the cursor position is displayed on the screen in engineering coordinates. As you move the mouse, the cursor position is updated. You can then "draw" your problem on the screen by moving and clicking the mouse.
CAD是一种计算机辅助绘图工具，GEO-SLOPE在SEEP/W中使用了Microsoft Windows用户绘图界面补充了类似于CAD的功能特性。这意味着在计算机中定义你的问题就像在纸上画图一样，屏幕是纸鼠标是笔。一旦你的纸面大小和工程比例被确定，工程坐标屏幕上会显示光标位置，随着你移动鼠标，光标位置相应更新，这样，你会在屏幕上通过移动并点击鼠标画出你的问题。
The following are some of the model definition interface features:
• Display axes, snap to a grid, and zoom.
To facilitate drawing, x and y axes may be placed on the drawing for reference. Using the mouse, axes may be selected, then moved, resized or deleted. For placing the mouse on precise coordinates, a background grid may be specified. Using a "snap" option, the mouse coordinates will be set to exact grid coordinates when the mouse cursor nears a grid point. To view a smaller portion of the drawing, it is possible to zoom in by using the mouse to drag a rectangle around the area of interest. Zooming out to a larger scale is also possible.
下面是一些定义界面特征的模式
显示轴，捕捉一个网格，并且视图
为了方便画图，x and y 轴会被置于图中便于提示，使用鼠标，选定坐标轴，移动，定义大小或删除。如果鼠标被放在精确的坐标上，显示背景网格，使用捕捉，当鼠标光标靠近一个网格点，鼠标坐标会被设定为确定的网格点，为了显示图形的某一小部分，可以通过使用鼠标在该区域画一个方格，放出一个大的刻度也是可以的。

• Sketch graphics, text and import picture.
Graphics and text features are provided to aid in defining models and to enhance the output of results. Graphics such as lines, circles and arcs, are useful for sketching the problem domain before defining a finite element mesh. Text is useful for annotating the drawing to show information such as material names and properties among other things. A dynamic text feature automatically updates the project information text on the drawing whenever the project information is changed. This ensures that the project information shown on the drawing always matches the project settings used in the model.

绘草图，文字和重要图
图文特征的提供有助于定义模型和保证输出结果，像线条、园、弧对于在定义有限单元望个以前草绘问题要素非常有用。文字用来陈述图片信息如土体名称、特性，一旦主体信息被改变，一个动态的文字特征自动更新图中的主题信息文本，这样保证了所显示的主题信息文本综合模型使用的主题相匹配。
The import picture feature is useful for displaying graphics from other applications in your drawing. For example, a cross-section drawing could be imported as a DXF file from AutoCAD for use as a background graphic while defining the problem domain. This feature can also be used to display things like photographs or a company logo on the drawing. Pictures are imported as an AutoCAD DXF file, a Windows bitmap (BMP) file, an enhanced metafile (EMF), or a Windows metafile, (WMF).
Using the mouse, individual or groups of graphics and text objects may be selected, then moved, resized or deleted.
重要的图片特征便于从图中其他应用中显示图形，例如，当定义模型要素时，一个网格部分可以输出为DXF文件便于AutoCAD作为图纸背景使用，这种特征也可被用来在图中显示比如图片或公司logo，图片可以被输出为：AutoCAD DXF、BMP、EMF、WMF等格式。

• Graphical finite element mesh generation and editing.
After the problem has been sketched, the problem domain must be discretized into a finite element mesh. To facilitate this, quadrilateral and/or triangular regions are drawn in the problem domain. Inside each region, any number of finite elements can automatically be generated. Individual or groups of nodes and elements may be moved or deleted using the mouse to select and drag these objects. The figure below shows how a quadrilateral region is interactively meshed with quadrilateral elements.
图形有限元网格的生成和编辑
问题一旦被草绘，问题要素必须被分配到有限单元网格中，为了便于做到这点，在问题要素中，通常被绘成矩形或三角形区，在每一个区内，任一个有限单元能自动绘出,单个或一组节点和单元可以通过鼠标选择或者拖动来进行移动或删除. 下图显示了一个矩形区如何被矩形单元网格化. Interactively?
• Graphical application of soil types and boundary conditions.
Each element in the mesh must be associated with a soil type. This can be accomplished using the mouse to select individual or groups of elements to which a soil type will be assigned. Boundary conditions can also be assigned to nodes and edges using the mouse. The figure below shows the application of a fixed 0.3 m total head boundary condition being applied to node 10
土壤类型和边界条件的图形应用
网格中的每个单元必须和一种图形关联,通过使用鼠标选择单个或一组单元到指定土壤类型中来完成,边界条件也可以使用鼠标分配节点和边,下图显示了一个节点10具有0.3米总水头的边界条件.
• Graphical and keyboard editing of functions.
SEEP/W makes extensive use of functions. For example, boundary conditions can be a function of time, and hydraulic conductivity is a function of pore-water pressure. All these functions can be edited graphically using the mouse and exact numerical values can be input using the keyboard. The figure below shows a point on a conductivity function being moved using the mouse.
图形和键盘的编辑函数

SEEP/W使用了大量的函数,比如,边界条件可以是时间的函数,导水性可以使孔隙水压力的函数.所有这些函数可以使用鼠标编辑图形,其特征值可以通过键盘输入,下图表示使用鼠标导水性函数中一个点被移动的例子.

未完!