[下载]2D间接边界元和位移连续性分析软件Examine2D

changqing

下载：2D间接边界元和位移连续性分析软件Examine2D，Free software
http://www.rocscience.com/downlo ... amine2Dv7004j26.exe

继往开来

Examine2D Program Overview

Examine2D is a 2-dimensional plane strain indirect boundary element program for the elastic stress analysis of underground excavations. Although Examine2D is primarily geared towards the analysis of excavations in rock, it can also be used for soil applications.

Before launching into an analysis with Examine2D, it is important to stop and consider the developmental philosophy of the program, the assumptions inherent in the analysis and the resultant limitations.

Examine2D is designed to be a quick and simple-to-use parametric analysis tool for investigating the influence of geometry and in-situ stress variability on the stress changes in rock due to excavations. The induced stresses in the plane of the analysis can be viewed by means of stress contour patterns in the region surrounding the excavations. As a tool for interpreting the amount of deviatoric overstress (principal stress difference) around openings, strength factor contours give a quantitative measure of (strength)/(induced stress) according to a user defined failure criterion for the rock mass. Displacement vectors and deformed boundary shape can be plotted to illustrate general deformation trends.

Some important limitations of the program which should be considered when interpreting Examine2D output are described below.

The assumption of plane strain means that the modelled excavation is of infinite length normal to the plane section of the analysis. In practice, as the out-of-plane excavation length becomes less than five times the largest cross-sectional dimension, the stress changes calculated by Examine2D begin to show some exaggeration since the real stress flow around the ‘ends’ of the excavation is not taken into account. All of the stress is ‘forced’ to flow around the excavation parallel to the analysis plane. This exaggeration becomes more pronounced as the out-of-plane length approaches the same magnitude as the in-plane dimensions. As long as this effect is kept in mind, the analysis may still yield useful insight into behaviourial trends in these cases.

The elastic boundary element analysis used in Examine2D dictates that the material being modelled is assumed to be:

homogenous

isotropic or transversely isotropic

linearly elastic

Obviously, most of the rock masses which will be modelled possess none of these properties. The degree to which the actual rock mass being modelled deviates from these assumed properties should be kept in mind when interpreting Examine2D output. Nevertheless, the induced stresses calculated and displayed by Examine2D can usually prove useful, for example, when optimizing excavation geometry and/or sequencing to avoid overstress and undesirable de-stressing.

The displacements shown by Examine2D are meant to qualitatively illustrate regional deformation trends only. The actual values of the displacements calculated by Examine2D include only the elastic displacements due to the excavation. This, in reality, may constitute a very small component of the actual measured displacements in the field. In weak broken rock, the actual magnitude of displacements may be several orders of magnitude greater than the calculated elastic values. In addition, the calculated displacements depend directly on the value of the Deformation (Young's) Modulus for the rock mass, a value difficult to estimate.

The practice of performing multiple analysis runs using a range of stress and material properties to study the effect of each parameter is a prudent one in all cases.

In short, Examine2D is a powerful but, nevertheless, limited tool. Like all numerical models, it should be used to enhance and supplement, but never to replace, common sense and good engineering judgement.

What Can I Do with Examine2D ?

To summarize, Examine2D has the following analysis and modeling capabilities:

single material with isotropic properties

elastic stress / displacement analysis

strength factor (overstress based on elastic results), using Mohr-Coulomb or Generalized Hoek-Brown failure criteria

constant or gravitational in-situ stress

interactive modeling and parametric analysis

uniform pressure loading

What Can I NOT Do with Examine2D ?

The following analysis and modeling capabilities are NOT available in Examine2D:

multiple materials

plasticity / yielding / progressive failure

support (bolts, liners, geotextiles, shotcrete)

staging

joints

pore pressure

generalized loading

For full featured stress analysis of underground or surface excavations, including the above features and much more, use the Rocscience finite element program Phase2. See the Rocscience website for details.

[ 本帖最后由 继往开来 于 2007-1-25 02:27 编辑 ]

dzg1578

好像是Demo版本吧,有限制的
不过学学还是很不错的~