The CSIRO originally developed the HI Cell for three-dimensional stress measurement in rock or concrete, and for decades it has produced the best results for managing safety in high rock stress mines, as well as being used to monitoring stress and strain in concrete tunnels and other structures.
The highly sensitive strain gauges are bonded to the rock in an ingenious mechanical process using temperature-specific glue packs, allowing the gauges to become part of the rock very rapidly. The gauge can be left in-situ for long term stress change measurement, or can be over-cored to see the strain change to determine a stress profile of that section of rock.
The HI Cell requires a strain bridge monitor to read the values, or a digital version, the HID Cell, can be used and logged using a breakout box and tablet, PC or serial data logger. Software for data analysis is also available.