The grant from the Investment Bank of the State of Brandenburg (ILB No. 85053766) enabled the acquisition of a high-pressure, high-temperature 3D True Triaxial Press facility at the GFZ, which is to be expanded beyond the scope of the project in a modular fashion and additionally utilised in a national cluster.

To this end, the core elements of a national high-pressure triaxial press cluster were set up and put into operation as part of this project. This includes a modularly expandable, cubic, polyaxial high-pressure testing facility for carrying out stress-strain analyses on rock samples under real triaxial pressure conditions with control options in all three main stress directions.

The facility is used to carry out highly specialised, experimental pressure tests on rocks, e.g. from boreholes. The experiments open up previously unattainable dimensions. The facility is coupled with a system for measuring acoustic emissions and a flow-through system. This makes the facility unique in Germany and even unique in the world. In addition, a surface grinder and a lathe will be purchased and put into operation for sample preparation and for setting up the experiments.

The uniqueness of the experimental facility results from the fact that a real true triaxial press operates in a high pressure and temperature range and is simultaneously coupled with

a) an acoustic emission (AE) system
b) a flow-through system to quantify fluid-rock interaction, and
c) a hydraulic stimulation simulation module.

With the mechanical testing system (MTS) hydrostatic pressures up to 140 MPa and temperatures up to 200 °C can be simulated. The pressure and temperature within the chamber are continuously monitored by an external pressure sensor and two internal
thermocouples (Type K). Within the pressure chamber, the thermocouples are located at top and bottom of the test specimen. To measure the axial and lateral strains of the sandstone samples, two axial extensometers and one circumferential chain extensometer were installed during all tests. The hydraulic system Quizix C-6000-10 K is connected to the pore pressure ports. Quizix C-6000-10 K enables fluid volume measurements with a resolution of 0.0000135 ml up to maximum flow rates of 200 ml/min. The maximum possible pore pressure is 68.9 MPa with a static accuracy of 0.06%.