Stratigraphy_surface_load
Contents
Data Structure: Stratigraphy_surface_load |
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Description |
Defines the loading associated with the top surface horizon |
Usage |
Stratigraphy_surface_load NUM=ival where ival is the data structure number |
Description |
Overview Stratigraphy_surface_load is used to define loading and boundary conditions associated with the top surface horizon for the model. Surface load types include: •Applied mechanical stress •Surface temperature •Surface pore pressure
Notes •One Stratigraphy_surface_load data structure is defined but it can be respecified for each stage. •When stratigraphy is defined and the porous flow field is active a prescribed pore pressure condition is applied to the surface horizon by default. The pore pressure will be either zero if no water level is defined, or computed using the current water level if it is defined. Standard pore pressure loading keywords using Global_loads for the top surface should not be defined at the same time. If both are defined, the stratigraphy pore pressure condition will take precedence. •When stratigraphy is defined and the porous flow field is inactive, pore pressure can be defined using either Stratigraphy_surface_load or the standard pore pressure loading keywords (see Global_loads). •When stratigraphy is defined and the thermal field is active, a prescribed temperature condition is applied to the surface horizon by default. Standard thermal loading keywords using Global_loads for the top surface should not be defined at the same time. If both are defined, the stratigraphy temperature loading will take precedence. •When stratigraphy is defined and the thermal field is inactive, temperature can be defined using either Stratigraphy_surface_load or the standard thermal loading keywords (see Global_loads).
Examples None
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 | Applied_stress Mechanical surface pressure |
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Description |
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Defines the value of the mechanical surface pressure. This may be defined either as an instantaneous load or with a load curve assigned using a time curve via Time_curve_stress.
Notes •In most example models, a prescribed small surface stress is recommended in order to prevent near surface material flow problems (e.g. when the stresses become positive). The stress is usually set to be equivalent to the load that represents the top 50m - 100m of sediment.
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| Time_curve_stress Time curve name or number for the mechanical surface pressure |
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Description |
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Assigns a time curve that defines the variation of the Applied_stress as a function of time. If not defined the applied mechanical stress is applied as an instantaneous load.
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| Pore_pressure_flag Flag indicating that the surface horizon has prescribed pore pressure |
Usage |
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Description |
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Flag indicating whether the surface horizon is assigned a prescribed pore pressure. Valid values are: • 0 - No prescribed pore pressure • 1 - Prescribed pore pressure (Default)
Notes •A prescribed pore pressure condition is applied to the surface horizon by default. The pore pressure will be either zero if no water level is defined, or computed using the current water level if it is defined. •If the porous flow field is inactive Pore_pressure_flag has no impact on the simulation.
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| Temperature_flag Flag indicating that the surface horizon has prescribed temperature |
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Description |
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Flag indicating whether the surface horizon is assigned a prescribed temperature. Valid values are: • 0 - No prescribed temperature • 1 - Prescribed temperature (Default)
Notes •A prescribed temperature condition is applied to the surface horizon by default. The temperature is defined by the Temperature keyword. •If the thermal field is inactive Temperature_flag has no impact on the simulation.
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| Temperature Top surface horizon temperature |
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Description |
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Defines the prescribed top surface horizon temperature. This may be defined either as an instantaneous load or with a load curve assigned using a time curve via Time_curve_temperature.
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| Time_curve_temperature Time curve name or number for the surface horizon temperature |
Usage |
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Description |
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Assigns a time curve that defines the variation of the top surface temperature as a function of time. If not defined the temperature is applied as an instantaneous load.
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| Fault_load_flag Flag to apply surface horizon loading to surface fault |
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Description |
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Flag indicating that the top surface loading should be applied to exposed fault surfaces that intersect the surface. Valid values are: • 0 - No loading applied to faults exposed at top surface (default) • 1 - Apply loads to exposed faults surfaces
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| Top_surf_average_volume_flag Flag to apply surface horizon loading to surface fault |
Usage |
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Description |
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When specified as non-zero this flag ensures that all tetrahedral connected to the top surface of the model are treated as standard TMP3 elements to improve stability •0 - No special treatmeent for top surface elements •1 - Ensure top surface elements are standard TPM3
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