This document details Datarock’s product Joint Roughness Coefficient (JRC) Proxy.
Literature
This product is based on the following literature:
|
Title |
Author |
Year |
|---|---|---|
|
The Shear Strength of Rock Joints in Theory and Practice |
Barton & Choubey |
1976 |
|
A new method estimating the 2D Joint Roughness Coefficient for discontinuity surfaces in rock masses |
Zhang et al |
2014 |
The outputs of the following models are used:
|
Model Name |
Model Type |
|
Fracture Detection and Classification |
Object Detection |
|
Drillers Break |
Object Detection |
|
Fracture Mask |
Instance Segmentation |
Data Processing
The following steps are taken to determine the JRC:
-
Take the output of the fracture detection model, “simple” classes only
-
Run a segmentation model predicting the fracture itself, then post process into a binary mask/overlay. The edges of this overlay are known as skeletons.
-
Fit an ellipse to left and right skeletons
-
Check for core neatness: plot each ellipse on stereonet, if tight fit, proceed to the next step. If not, discard this joint for measurement.
-
Check for neatness of fit of the ellipse to the skeleton. If outside of threshold, do not proceed.
-
Straighten out profile of ellipse, fracture profile interface
7. Calculate the JRC_median, JRC_lower_bound, JRC_upper_bound for each. This provides a score from 0-20.
Product Configuration Options
There are no configuration aspects to this product.
Output Data
Fracture point data
User Data
Not currently able to upload to the platform.
Data Output
Results from this product is delivered in a batch nature.
Integration of the required technologies into Datarock production is ongoing.
The available CSV files include the following:
-
ProjectName_jrc.csv
|
File Header |
Description |
|---|---|
|
hole_id |
Customer’s Hole ID |
|
depth_m |
Depth of fracture (metres) |
|
depth_ft |
Depth of fracture (feet) |
|
jrc_left_s |
Left side of fracture: suggested (median) JRC measurement |
|
jrc_left_u |
Left side of fracture: upper bound JRC measurement. The statistical upper bound of the potential range of JRC values based on this method. |
|
jrc_left_l |
Left side of fracture: lower bound JRC measurement. The statistical lower bound of the potential range of JRC values based on this method. |
|
jrc_right_s |
Right side of fracture: suggested (median) JRC measurement |
|
jrc_right_u |
Right side of fracture: upper bound JRC measurement. The statistical upper bound of the potential range of JRC values based on this method. |
|
jrc_right_l |
Right side of fracture: lower bound JRC measurement. The statistical lower bound of the potential range of JRC values based on this method. |
|
jrc_left_error |
Fit score of the ellipse fitting to the left skeleton. |
|
jrc_right_error |
Fit score of the ellipse fitting to the right skeleton. |
|
selected_side |
The selected side of the fracture for reporting final JRC measurements. |
|
jrc |
The suggested JRC measurement of the selected side of the fracture. |
|
fracture_uuid |
Universally unique identifier for the fracture |
Product Limitations
|
Limitations |
Comments |
|---|---|
|
Measurement on “simple” fractures only |
This method is limited to fractures that have one interface only, as we need a clear interface to measure. There may be intervals of broken rock that have different JRC values |
|
Analysing interface of fracture with edge of core |
The nature of this method relies on a direct correlation between a fracture’s internal roughness and the appearance of its interface with the circumference of the core. A comparison with logged data across the customer’s range of lithology is required. |
|
Version |
Date |
Author |
Rationale |
|---|---|---|---|
|
1 |
7 Sep 2022 |
S Johnson |
Initial release |
|
2 |
29 January 2024 |
S Johnson |
Updated to include depth in feet |