Geotechnical Function – EQUIS.GEOTECH_CPT_DISSIPATION_DATA

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Geotechnical Function – EQUIS.GEOTECH_CPT_DISSIPATION_DATA

Purpose

 

The EQUIS.GEOTECH_CPT_DISSIPATION_DATA function queries the results of a Cone Penetration Test (CPT) Dissipation test to calculate the pore pressure and normalized excess pore pressure results. The test results are queried from the DT_GEO_RESULT, DT_GEO_TEST, and DT_GEO_TEST_PARAMETER tables.

 

The EQUIS.GEOTECH_CPT_DISSIPATION_DATA function creates a function report called Geotechnical CPT Dissipation Data. It is also used in the Geotechnical CPT - Pore Pressure Dissipation report.

 

 

Calculation Details

 

The function uses the Dissipation pore pressure (DT_GEO_RESULT.GEO_RESULT_CODE = ‘cpt_dis_pp’) to report the Pore Pressure. The DT_GEO_RESULT.GEO_RESULT_CODE = ‘cpt_dis_pp’ values must be stored in KPa. The Normalized Excess Pore Pressure values are calculated by using an Initial Pore Pressure Override value (DT_GEO_TEST_PARAMETER.PARAM_CODE = ‘cpt_dis_initial_pp_override’). If this value is not provided, then the function uses the initial pore pressure reading to determine the Normalized Excess Pore Pressure.

 

A Water Depth value must be provided in DT_GEO_TEST_PARAMETER.PARAM_CODE = ‘cpt_dis_assu_wat_dep’ for the function to compute. The water depth is assumed to be in the same units as the associated DT_GEO_TEST.DEPTH_UNIT.

 

The function outputs the parameters based on the unit defined in DT_TASK_PARAMETER.PARAM_VALUE for DT_TASK_PARAMETER.PARAM_CODE = ‘cpt_output_unit’. The PARAM_VALUE must be either ‘E’ for English, or ‘M’ for Metric. If the value is empty, then the function will report the results in English units.

 

Note: The function only supports one record for DT_TASK_PARAMETER.PARAM_CODE = ‘cpt_output_unit’ per facility.

 

 

Function Outputs – CPT Dissipation Parameters

 

The following table lists the CPT dissipation parameters that the EQUIS.GEOTECH_CPT_DISSIPATION_DATA function outputs, including function field name, associated unit, and equation used (when applicable). If the function output is available in the database, this value will be used instead of calculating the value.

 

Field

Function
Field Name

Unit
(English/Metric)

Equation (if applicable)

Pore Pressure, u2

u2

TSF/MPa


Normalized Excess Pore Pressure, U

Normalized_excess_pore

TSF/MPa

Duration

duration

seconds