AGSi Guidance / Models¶
Models showing exploratory holes - Worked Example¶
Here is an example showing how to model exploratory holes, including their geology. For guidance on the underlying principles and use of the schema, refer to the previous page
In this simplified example, there are two boreholes with geology (three geological unit segments in each), as illustrated below. For one of the boreholes a profile of SPT N values with depth is provided.
A copy of the full JSON data file described below can be downloaded here.
Note
In the following the JSON data is broken up in to several sections to allow commentary to be provided. To ensure that the JSON data is formatted correctly it has been necessary to include an additional "{" or "[" at the top and/or bottom of some of the sections. For the correct version of full JSON file please use the link posted above.
Model metadata¶
This first section contains model metadata in the agsiModel object. For the purposes of this example, the holes are provided in their own standalone model. However, it should be noted that exploratory holes may be incorporated into other relevant models, e.g. the main geological (volume) model.
{
"agsiModel": [
{
"modelID": "ffcaa660-69b8-412a-9d32-dc906195bc0e",
"modelName": "Sitewide geological model - boreholes only",
"description": "C999 Package X Sitewide geological model - boreholes only.",
"coordSystemID": "MetroXYZ",
"modelType": "Geological model",
"category": "Observational",
"domain": "Engineering geology",
}]}
Observation set¶
We will be using observation group objects for the exploratory holes and their data, so we first need to establish an agsiObservationSet object within the parent agsiModel.
Here we use the investigationID attribute to reference the identifier of the agsProjectInvestigation object for the relevant ground investigation (we define this later).
{
"agsiObservationSet": [
{
"observationSetID": "Obs/GIHolesA",
"description" : "2018 GI Package A",
"investigationID": "GI Package A",
}]}
Exploratory holes¶
We then define the exploratory holes using agsiObservationExpHole objects embedded (as an array) within the parent agsiObservationSet. The first of our holes is defined in the snippet below.
{
"agsiObservationExpHole": [
{
"holeID": "A/BH01",
"holeName": "BH01",
"topCoordinate": [525275.5,181543.2,15.3],
"verticalHoleDepth": 25,
"holeType": "CP",
"date": "2018-05-23",
}]}
Geology (column segments)¶
The geological succession for this hole is now provided using an array of agsiObservationColumn objects embedded within the parent agsiObservationExpHole. In this example there is one segment object for each of the units encountered in the hole.
The codes used by legendCode and geologyCode are defined later.
{
"agsiObservationColumn": [
{
"topElevation": 15.3,
"bottomElevation": 13.5,
"description": "Very soft and soft brown, dark brown and grey slightly sandy slightly gravelly CLAY",
"legendCode": "102",
"geologyCode": "MG"
},
{
"topElevation": 13.5,
"bottomElevation": 8.9,
"description": "Soft brown silty sandy CLAY",
"legendCode": "207",
"geologyCode": "ALV"
},
{
"topElevation": 8.9,
"bottomElevation": -9.7,
"description": "Stiff to very stiff blue grey slightly sandy silty CLAY with rare claystone layers (<0.1m thick)",
"legendCode": "202",
"geologyCode": "GC"
}
],
}
Test (SPT) data¶
We now include some SPT N values for this hole, using the AGSi recommended approach of embedding an
agsiDataPropertyValue
object within the parent
agsiObservationExpHole.
The 'profile ' of N values within the hole is provided using the
valueProfile
attribute in which we provide an array of [Elevation,SPT N] pairs.
valueProfileIndVarCodeID
is used to confirm that the profile is defined by elevation.
Note
This example should not be taken as encouragement to include SPT data in a model. If there are good reasons for doing so, and it is agreed that it should be included, then ok. But if only SPTs are included, and not other test data that is just as important, then it should be questioned.
{
"agsiDataPropertyValue": [
{
"codeID": "ISPT_NVAL",
"valueProfileIndVarCodeID": "Elevation",
"valueProfile": [
[14.0,21],
[13.0,8],
[12.0,7],
[11.0,27],
[10.0,38],
[8.5,22]
],
"remarks": "Only a few reading shown here, for brevity"
}
]
},
Another hole¶
Here is the data for another hole, i.e. a new object within the parent agsiObservationSet. There is no SPT data included this time.
{
"holeID": "A/BH02",
"holeName": "BH02",
"topCoordinate": [525220.0,181550.0,17.2],
"verticalHoleDepth": 40,
"holeType": "CP+RC",
"date": "2018-05-27",
"agsiObservationColumn": [
{
"topElevation": 17.2,
"bottomElevation": 14.1,
"description": "Brown slightly clayey SAND with some subangular to subrounded fine to coarse fravel of flint, concrete and brick. Occasional subangular cobbles of concrete. ",
"legendCode": "102",
"geologyCode": "MG"
},
{
"topElevation": 14.1,
"bottomElevation": 9.4,
"description": "Very soft/loose brown sandy SILT",
"legendCode": "303",
"geologyCode": "ALV"
},
{
"topElevation": 9.4,
"bottomElevation": -22.8,
"description": "Stiff to very stiff blue grey silty CLAY",
"legendCode": "202",
"geologyCode": "GC"
}
]
}
]}]}],
Investigation¶
In the Exploratory holes snippet above we referenced the identifier of an agsProjectInvestigation object. We now define that object.
However, before doing so we must first define a parent agsProject object, in which agsProjectInvestigation is embedded.
{
"agsProject": {
"projectName": "C999 Geotechnical Package X",
"remarks": "Other project metadata omitted for brevity",
"agsProjectInvestigation": [
{
"investigationID" : "GIPackageA",
"investigationName" : "Gotham City Metro Purple Line, C999 Package A",
"contractor" : "Boring Drilling Ltd",
"remarks" : "Other GI metadata omitted for brevity"
}
],
}}
Codes¶
Finally, we provide the definitions for the codes that have been used in some of the data. Specifically:
- data property codes
- geology codes
- legend codes
- exploratory hole type codes
Note
The codes are defined at the end in this example, but this does not have to be the case as the order of objects in AGSi is not important. It would be acceptable to include this block of data at the start of the file.
The codes are defined using agsProjectCodeSet and agsProjectCode.
We will start with the codes used by agsiDataPropertyValue. First we establish the 'set' of codes using an agsProjectCodeSet object. In this example the codes used are in accordance with the AGSi standard code list, which is turn is based on the AGS (factual) format ABBR standard code list.
The codes themselves are defined using agsProjectCode objects embedded as an array within agsProjectCodeSet.
{
"agsProjectCodeSet": [
{
"description": "Property codes (AGS)",
"usedByObject": "agsiDataPropertyValue",
"usedByAttribute": "codeID",
"sourceDescription": "AGS ABBR standard code list",
"sourceURI": "https://www.ags.org.uk/data-format/ags4-data-format/ags-4-0-data-format/abbreviations/",
"agsProjectCode": [
{
"codeID": "ISPT_NVAL",
"description": "SPT N value",
"units": "Blows/300mm",
"remarks": "N value extrapolated where test terminated before full penetration"
},
{
"codeID": "Elevation",
"description": "Elevation",
"units": "mOD"
}
]
},
]}
{
"description": "Geology codes",
"usedByObject": "agsiObservationColumn",
"usedByAttribute": "geologyCode",
"sourceDescription": "Project geology code list",
"agsProjectCode": [
{
"codeID": "MG",
"description": "Made Ground"
},
{
"codeID": "ALV",
"description": "Alluvium"
},
{
"codeID": "GC",
"description": "Gotham Clay"
}
]
},
Finally the legend and hole type codes. Here we will simply reference the AGS (factual) format ABBR standard list of codes for each of these, given that they are well known.
Note
It would be arguably better practice to also include the codes themselves here. For the sake of brevity, we have not done so for this example.
{
"description": "Legend codes",
"usedByObject": "agsiObservationColumn",
"usedByAttribute": "legendCode",
"sourceDescription": "AGS ABBR standard code list",
"sourceURI": "https://www.ags.org.uk/data-format/ags4-data-format/ags-4-0-data-format/abbreviations/"
},
{
"description": "Exploratory hole types",
"usedByObject": "agsiObservationExpHole",
"usedByAttribute": "holeType",
"sourceDescription": "AGS ABBR standard code list",
"sourceURI": "https://www.ags.org.uk/data-format/ags4-data-format/ags-4-0-data-format/abbreviations/"
}
]
]
}
}
Version history¶
First formal issue, for v1.0.0 of standard, 30/11/2022.