4
Step 2 Mesh Generation
Mesh generation is automatic using an interactive mesh
generation program. Output includes all the files specifying
the mesh, a plot input file, a finite element runstream file
and a plot file for finite element output. The preexcavation
stress state is considered to be caused by gravity alone and
is thus related to the specific weights assigned to the vari-
ous formations, formation thicknesses and to the Poisson’s
ratios. For example in case of no joints, the vertical stress
at the mining horizon is 1471 psi (10.1 MPa) horizontal
stresses are 490 psi (3.4 MPa).
Figure 7 illustrates the finite element mesh in cross-
section near the shaft bottom. The shaft is filled with gray
elements that are excavated during analysis. Excavation
proceeds in three successive cuts of approximately 500 ft
each from the bottom up. The reason is the shaft was pulled
from the bottom up and not sunk from the top down in
a conventional shaft sinking manner. There are 1,472,000
three-dimensional elements and 1,506,753 nodes in the
mesh.
Step 3 FEM Execution, Results
The runstream file produced during mesh generation is
Solvay shaft to surface (1500 ft) cut 26 ft D 1/30/2024 wgp
F:\Visual Studio 2010\Projects\SPK\GHS\TRj.txt
F:\Visual Studio 2010\Projects\SPK\GHS\relms
F:\Visual Studio 2010\Projects\SPK\GHS\rcrds
F:\Visual Studio 2010\Projects\SPK\GHS\rctel
F:\Visual Studio 2010\Projects\SPK\GHS\rsigi
F:\Visual Studio 2010\Projects\SPK\GHS\rnsps
Aj3
nelem =1472000
nnode =1506753
nspec =57478
nmat =12
ncut =-1
ninc =5
nisgo =1
inter =200
maxit =2000
Table 1. Equivalent jointed rock properties (continued)
(3) SANDSTONE 1
0.784E+06 0.784E+06 0.659E+06 0.26 0.09 0.08
0.185E+06 0.185E+06 0.296E+06 0.00 0.00 140.0
2441.1 2441.1 2051.5 185.5 185.5 155.9
388.5 388.5 326.5
0.0 0.0 210.0 249.0
(4) OIL SHALE 1
0.498E+06 0.498E+06 0.445E+06 0.31 0.20 0.18
0.136E+06 0.136E+06 0.185E+06 0.00 0.00 142.0
3211.9 3211.9 2870.3 279.2 279.2 249.5
546.7 546.7 488.6
0.0 0.0 459.0 449.0
…
(7) TRONA 1
0.976E+06 0.976E+06 0.788E+06 0.27 0.06 0.05
0.208E+06 0.208E+06 0.362E+06 0.00 0.00 134.0
1627.4 1627.4 1314.8 98.1 98.1 79.2
230.6 230.6 186.3
0.0 0.0 1499.0 10.0
(8) OIL SHALE 2
0.498E+06 0.498E+06 0.445E+06 0.31 0.20 0.18
0.136E+06 0.136E+06 0.185E+06 0.00 0.00 142.0
3211.9 3211.9 2870.3 279.2 279.2 249.5
546.7 546.7 488.6
0.0 0.0 1509.0 89.0
(9) TRONA 2
0.976E+06 0.976E+06 0.788E+06 0.27 0.06 0.05
0.208E+06 0.208E+06 0.362E+06 0.00 0.00 134.0
1627.4 1627.4 1314.8 98.1 98.1 79.2
230.6 230.6 186.3
0.0 0.0 1598.0 10.0
…
(12) TIPTON FM
0.516E+06 0.516E+06 0.460E+06 0.24 0.14 0.12
0.144E+06 0.144E+06 0.202E+06 0.00 0.00 144.0
3138.5 3138.5 2795.1 272.8 272.8 243.0
534.2 534.2 475.8
0.0 0.0 1847.0 3313.0
Figure 7. Finite element mesh in cross-section at shaft
bottom. White elements are rock mass elements. Grey
elements are excavated or “cut” elements. Unlined shaft
diameter is 26 ft (7.9 m)
Step 2 Mesh Generation
Mesh generation is automatic using an interactive mesh
generation program. Output includes all the files specifying
the mesh, a plot input file, a finite element runstream file
and a plot file for finite element output. The preexcavation
stress state is considered to be caused by gravity alone and
is thus related to the specific weights assigned to the vari-
ous formations, formation thicknesses and to the Poisson’s
ratios. For example in case of no joints, the vertical stress
at the mining horizon is 1471 psi (10.1 MPa) horizontal
stresses are 490 psi (3.4 MPa).
Figure 7 illustrates the finite element mesh in cross-
section near the shaft bottom. The shaft is filled with gray
elements that are excavated during analysis. Excavation
proceeds in three successive cuts of approximately 500 ft
each from the bottom up. The reason is the shaft was pulled
from the bottom up and not sunk from the top down in
a conventional shaft sinking manner. There are 1,472,000
three-dimensional elements and 1,506,753 nodes in the
mesh.
Step 3 FEM Execution, Results
The runstream file produced during mesh generation is
Solvay shaft to surface (1500 ft) cut 26 ft D 1/30/2024 wgp
F:\Visual Studio 2010\Projects\SPK\GHS\TRj.txt
F:\Visual Studio 2010\Projects\SPK\GHS\relms
F:\Visual Studio 2010\Projects\SPK\GHS\rcrds
F:\Visual Studio 2010\Projects\SPK\GHS\rctel
F:\Visual Studio 2010\Projects\SPK\GHS\rsigi
F:\Visual Studio 2010\Projects\SPK\GHS\rnsps
Aj3
nelem =1472000
nnode =1506753
nspec =57478
nmat =12
ncut =-1
ninc =5
nisgo =1
inter =200
maxit =2000
Table 1. Equivalent jointed rock properties (continued)
(3) SANDSTONE 1
0.784E+06 0.784E+06 0.659E+06 0.26 0.09 0.08
0.185E+06 0.185E+06 0.296E+06 0.00 0.00 140.0
2441.1 2441.1 2051.5 185.5 185.5 155.9
388.5 388.5 326.5
0.0 0.0 210.0 249.0
(4) OIL SHALE 1
0.498E+06 0.498E+06 0.445E+06 0.31 0.20 0.18
0.136E+06 0.136E+06 0.185E+06 0.00 0.00 142.0
3211.9 3211.9 2870.3 279.2 279.2 249.5
546.7 546.7 488.6
0.0 0.0 459.0 449.0
…
(7) TRONA 1
0.976E+06 0.976E+06 0.788E+06 0.27 0.06 0.05
0.208E+06 0.208E+06 0.362E+06 0.00 0.00 134.0
1627.4 1627.4 1314.8 98.1 98.1 79.2
230.6 230.6 186.3
0.0 0.0 1499.0 10.0
(8) OIL SHALE 2
0.498E+06 0.498E+06 0.445E+06 0.31 0.20 0.18
0.136E+06 0.136E+06 0.185E+06 0.00 0.00 142.0
3211.9 3211.9 2870.3 279.2 279.2 249.5
546.7 546.7 488.6
0.0 0.0 1509.0 89.0
(9) TRONA 2
0.976E+06 0.976E+06 0.788E+06 0.27 0.06 0.05
0.208E+06 0.208E+06 0.362E+06 0.00 0.00 134.0
1627.4 1627.4 1314.8 98.1 98.1 79.2
230.6 230.6 186.3
0.0 0.0 1598.0 10.0
…
(12) TIPTON FM
0.516E+06 0.516E+06 0.460E+06 0.24 0.14 0.12
0.144E+06 0.144E+06 0.202E+06 0.00 0.00 144.0
3138.5 3138.5 2795.1 272.8 272.8 243.0
534.2 534.2 475.8
0.0 0.0 1847.0 3313.0
Figure 7. Finite element mesh in cross-section at shaft
bottom. White elements are rock mass elements. Grey
elements are excavated or “cut” elements. Unlined shaft
diameter is 26 ft (7.9 m)