Welcome to Apeiron. In this tutorial, we will explore using the CPT Liquefaction Calculator module within a Project, providing you with a comprehensive overview of its functionalities and features.
Introduction
Accessing the Liquefaction Calculator Module
The CPT Liquefaction Calculator is a design module. All design modules live within Design Scenarios, which in turn live within Project Stages. A Project Stage can have any number of Design Scenarios, but each Design Scenario can only have one copy of each type of design module. This ensures that you always know where data is coming from in situations where one module is pulling data from another.
To add a CPT Liquefaction Calculator module, click on the plus button next to the design modules header within a Design Scenario, then select 'CPT Liquefaction Calculator' in the pop-up. Give it a name and click Create.
Adding Investigations
When you go into the CPT Liquefaction Calculator module, you will be taken to the select page. Here, leverage the investigation data prepared in the Dataset module, handpicking specific investigations for inclusion in the liquefaction assessment.
If you would like to include additional investigations, you must go back to your Dataset module for this Stage and add them there first.
If an investigation is not selectable, this is because it was added to the Dataset but was not analysed. Go back to the Dataset module for this Stage and analyse it first if you would like to include that investigation in your CPT Liquefaction Calculator.
Analysis Tabs
General Settings
The fundamental analysis inputs common to all CPTs are configured in the general settings tab.
- Design Groundwater Level: Specify the groundwater level during seismic events in either meters below ground level for each CPT or a uniform elevation for all CPTs.
- Seismic Input: Input peak ground acceleration, earthquake magnitude, and corresponding return period for a single set of analysis parameters.
- Applied Stress: Choose one of surcharge, cut or fill for all CPTs. If you don't want any, then leave surcharge selected with a value of 0.
- Sensitivity Analysis: Configure seismic shaking and design groundwater level sensitivity analysis by defining multiple cases.
- Earthquake Shaking: In seismic shaking sensitivity analysis, additional cases can be configured by specifying the peak ground acceleration, magnitude and return period. If 'varying magnitude' is disabled, the same magnitude as the baseline case is assumed.
- Design Groundwater: In design groundwater level sensitivity analysis, you can specify an upper bound and lower bound for the design groundwater level, as well as the interval between each case. This will automatically generate multiple sensitivity cases.
- Liquefaction Susceptibility Setting: Define the default Ic cut-off value used to calculate liquefaction susceptibility for all CPTs.
These parameters, including design groundwater level, seismic input, applied stresses, sensitivity analysis, and Ic cutoff value, can be adjusted for individual CPTs in the following tabs.
Groundwater
In the Groundwater tab, you can customize the design groundwater level for individual CPTs if you want them to differ from the value that you supplied in the general settings tab. Any modifications related to groundwater during the investigation redirect you to the Dataset module. This is because the Dataset module should be the single source of truth for all other modules within the Project Stage.
Inverse Filtering
The Inverse Filtering tab allows a detailed view of cone resistance and sleeve friction traces adopted for analysis, pulled directly from the Dataset module. Once again, if you disagree with any of these options, you can change them in the Dataset, but be aware that this will affect all other modules in the Stage as well.
Stress
Review and modify vertical total stress and vertical effective stress in the Stress tab, utilizing the stress profile calculated based on unit weight from the Dataset module and applied stress settings. For each CPT, you can either choose to adopt the applied stress settings from the general setting tab or modify it with a different value specific to this CPT.
Susceptibility
Tailor layer susceptibility for individual CPTs in the Susceptibility tab, with default values derived from the General Settings tab. However, different layers can also be manually defined as susceptible or non-susceptible to liquefaction. A different Ic cut-off value can also be manually assigned for specific depth for individual CPTs.
If Plasiticy Index from laboratory testing data are available, they can also be plotted on a graph adjacent to the Ic graph for reference so that you can quickly compare whether the susceptibility settings are consistent with the Plasiticity Index values from laboratory test results. For example, if a layer has a Plasticity Index of 20 but is still shown as susceptible to liquefaction, you can identify the inconsistency early in the design process.
Fines Content Correction
The Fines Content Correction tab allows you to review the fines content that will be adopted in the analysis. If you want to update the fines content, click on the edit button, and you will be directed back to the Dataset module in the same Project Stage.
Custom CSR and CRR
The Custom CSR and CRR feature is still under development and will be released soon.
Assessment Methods
Finally, in the Assessment Methods tab, you can select the methodology you would like to use for your design.
This is also the tab where you start the final analysis. Once you are happy with the methodology, save the design module using the save icon in the top right corner and then click the Analyse All button. The analysis may take up to a few minutes to complete, however, you are free to leave this page and come back at any time without disrupting your analysis.
Upon successful completion, click the View Results button to switch to the results view.
Results
In the results view, you will be able to view the correlated parameters for all the investigations in your Dataset module. You may have to scroll horizontally or zoom out to view all of the results graphs, depending on the size of your screen.
Switch between different CPTs using the selected CPT dropdown. You can also fix the vertical axis and choose to view in elevation rather than depth when viewing the output graphs.
You can return to the analysis view at any time by clicking on the Return to Analysis button at the bottom of the page.
Currently, only the Liquefaction Assessment tab, the Soil Behaviour Index tab, the Damage Indicators tab, and the Settlements and Lateral Displacements tabs are available. If sensitivity cases are defined in the analysis, use the scroll bar to see results from different sensitivity cases. If both design groundwater level and shaking sensitivity analysis are performed, you can view the liquefaction analysis results from any combination of ground shaking intensity and design groundwater level.
Export Results
Results can be exported for further external manipulation if needed. To do so, click on the Generate Output button inside the results view. Choose which investigations you would like to include in your output, and then click generate on the type of output you would like. Excel export is available now, while PDF export will be made available in the coming weeks.
It may take up to a minute to generate your output. Once it is ready, click the download latest output button to save a copy of the analysis results to your computer.
Conclusion
Those are the basics of the CPT Liquefaction Calculator module! Stay tuned for forthcoming features, including the Custom CSR and CRR functionality, set to be released soon. If you need further support or have any suggestions, then please contact us by submitting a request in the top right-hand corner or by emailing support@infinitystudio.ai.