Case2 Restoration with Bedding Plane Slip
Contents
The data file for this exercise is located in Rest_001/Exercices/Case2/Data. Look for ! TODO text in the datafile and follow the instructions.
In this exercise a distributed bedding plane slip model will be used to allow bedding plane slip within formations. This will be achieved by:
1Defining the bedding plane coordinate system and assigning it to the groups
2Defining a fracture set at bedding plane and assigning it to the material model "Elastic"
Coordinate system definition and assignment
Data File |
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* Group_data NUM=4 ! ---------------------------------- Group_name "formation4" Element_type TPM3V Material_name "Elastic" Surfaces IDM=2 1 2 Porous_flow_type 5 Material_rotation_flag 1 Material_coord_system 1
* Coordinate_system NUM=1 ! ---------------------------------- Reference_orientation "Bedding" Direction_cosines IDM=2 JDM=2 1.000 0.000 0.000 1.000
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1A local coordinate system is defined for the bedding plane. The axis for such coordinate system are defined to coincide with the X and Y axis by defining the direction cosines. 2The coordinate system number 1 is assigned to all groups (here only one group is shown) by specification of the keyword Material_coord_system = 1. 3The Material_rotation_flag is set to 1 so rotation of the local coordinate system will be performed according to the bedding plane (according to the upper and lower stratigraphy horizons). |
Fracture set definition and assignment
Data File |
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* Material_data NUM=1 ! --------------------------------- Material_name "Elastic" Units IDM=4 /Stress/ "MPa" /Length/ "m" /Time/ "Ma" /Temperature/ "Celsius" Isotropic_elastic_properties IDM=2 /Young's Modulus/ 50000 /Poisson's Ratio/ 0.20 Grain_density 2760 Grain_stiffness 30000 Porosity 0.50 Singlephase_fluid 1 Fracture_set_names IDM=1 "Bedding"
* Fracture_data NUM=1 ! --------------------------------- Name "Bedding" Propagation_model_name "PreExist" Shear_strength_model "MaxShear" Shear_strength_properties NUM=1 /Max_shear_stress/ 150.0
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1A Fracture_data structure is defined in order to define the bedding plane "fractures" (bedding planes can be considered as pre-existing orientated fractures with a given maximum shear strength). 2The Propagation_model_name is set to "PreExist" for simulating bedding plane slip (bedding plane slip weakness already exists). 3A maximum shear strength model is invoked (if the shear stress exceed the maximum shear strength bedding plane slip occurs). 4The maximum shear strength is set to 150 MPa. |
Results
The result files for the project are in directory: Rest_001\Exercises\Case2\Results. Note how the bedding plane slip mechanism has allowed better preservation of the true formation lengths (see the shape of the lateral boundaries) and resulted in lower volumetric strain than in Case1.
Results for Case2. Groups (left) and Volumetric strain (right).
View of the bedding plane orientation at each mesh node.
Comparison of results for Case1 (top) and Case2 (bottom).
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