Sets up the Map3Di analysis.
Map3Di allows one to superimpose external field loading effects into the Map3D model. For details on this feature refer to Map3Di.
When you check a Map3Di loading file for use you will be prompted to search for a file name, location. If the search is successful, the file will be checked.
The Map3Di loading file is specified in polyline file format. Refer to Contour Plane Options for details on generating a Map3Di loading file.
Comment lines must start with an asterisk "*" in column 1.
2D planes are stored as a series of triangle or quadrilateral polylines as follows:
x1 y1 z1 3 values1
x2 y2 z2 2 values2
x3 y3 z3 2 values3
x4 y4 z4 2 values4
...
3D blocks are stored as a series of tetrahedral or hexahedral polylines as follows:
x1 y1 z1 3 values1
x2 y2 z2 2 values2
x3 y3 z3 2 values3
x4 y4 z4 2 values4
x5 y5 z5 1 values5
x6 y6 z6 1 values6
x7 y7 z7 1 values7
x8 y8 z8 1 values8
...
where xi yi zi represent the coordinates of each point.
3 indicates that this point is the beginning of a new polyline.
2 indicates that this point forms part of the base of the block.
1 indicates that this point forms part of the top of the block. This item is only used for definition of 3D block shapes.
Additional polylines are specified by repeating the sequence (i.e. starting a new polyline with the number 3).
Any of the points can be repeated or skipped to specify triangular shaped sides or tetrahedrons.
valuesi specifies the magnitude of the field loading at the centre, or at each corner. If only values1 is specified (i.e. values2 … are left blank) that value is applied uniformly across the entity.
If valuesi are specified for all corners, the field loading is applied according to a higher order polynomial distribution.
For 2D surface triangles a linear distribution is used
a + b x + c y
For 2D quadrilaterals, the following distribution is used
a + b x + c y + d x y
For 3D block shapes, as many terms as possible of the distribution are used
a + b x + c y + d z + e x y + f y z + g z x + h x y z
The actual field loading effects can be specified in several ways.
2D Planes
2D planes define a Displacement Discontinuity with specified normal displacement (closure) δn, and shear displacement (ride) δs, such that valuesi can be specified either as
δn δs or δn δs1 δs2
If only δn δs are specified, the shear displacement (ride) is applied parallel to the maximum in-plane shear stress for the 2D plane.
If all of δn δs1 δs2 are specified, the shear displacement (ride) component δs1 is applied parallel to the first side (i.e. the side defined by x1 y1 z1 – x2 y2 z2). δs2 is applied perpendicular to δs1 in the direction of the second side (i.e. the side defined by x2 y2 z2 - x3 y3 z3).
Shear displacement (ride) and normal displacement (closure) are specified in displacement units (i.e. the same units as the geometry is specified in (metres).
The shear displacement (ride) and normal displacement (closure) may be determined from in situ or laboratory measurements of shear, closure and/or crack opening, or from another numerical modelling program such as a reservoir or hydraulic fracture simulator. These can also be estimated from seismic monitoring data.
3D Blocks
3D blocks define a zone with specified strain ε, either as
ε1 ε2 ε3 or εxx εyy εzz εxy εyz εzx
If only ε1 ε2 ε3 are specified, these principal strains are applied parallel to the principal stresses. The strains are used to determine the initial stress σ° using
σ1° = [ (1-ν) ε1 + ν ( ε2 + ε3 ) ] E / [ (1+ν) (1-2ν) ]
σ2° = [ (1-ν) ε2 + ν ( ε3 + ε1 ) ] E / [ (1+ν) (1-2ν) ]
σ3° = [ (1-ν) ε3 + ν ( ε1 + ε2 ) ] E / [ (1+ν) (1-2ν) ]
If all of εxx εyy εzz εxy εyz εzx are specified, these strains are applied as Cartesian components. The strains are used to determine the initial stress σ° using
σxx° = [ (1-ν) εxx + ν ( εyy + εzz ) ] E / [ (1+ν) (1-2ν) ]
σyy° = [ (1-ν) εyy + ν ( εzz + εxx ) ] E / [ (1+ν) (1-2ν) ]
σzz° = [ (1-ν) εzz + ν ( εxx + εyy ) ] E / [ (1+ν) (1-2ν) ]
τxy° = εxy E / (1+ν)
τyz° = εyz E / (1+ν)
τzx° = εzx E / (1+ν)
Strains are specified in dimensionless strain units (i.e. 0.001 would specify 1000 micro strain).
E and ν represent respectively Young's (rock mass scale - deformation) modulus and Poisson's ratio. Map3D automatically determines which material the corner of the 3D block is located within and uses the corresponding material properties.
The strains may be determined from in situ or laboratory measurements of temperature or fluid pressure, or from another numerical modelling program such as a thermal analysis code. These can also be estimated from seismic monitoring data.
The strains that should be applied can be determined from the temperature through an expansion coefficient A, where the temperature change or fluid pressure change (from the background value) induces the initial stresses
σ1° = σ2° = σ3° = A ΔT
For fluid flow problems the expansion coefficient A, should be set to unity (positive one) for saturated media. For thermal problems the expansion coefficient should be specified as a negative quantity given by
A = α E /(1-2ν)
where α represents the coefficient of thermal expansion (i.e. the linear expansivity).
Notes
This function must be set up before conducting the Map3D BEM analysis
CAD > Properties > Map3Di Setup > View enables viewing of the Map3Di data.