Design and Application of a High-performance True Triaxial Stress Cell

Abstract

Conventional triaxial tests are for axisymmetric stress condition, which is not necessarily correct for deep rock layers. Thus, orthotropic stress conditions and pore pressure are better simulated by new generation of high-performance True Triaxial Stress Cell (TTSC). New TTSC in Curtin university allows stresses up to 70 MPa on a 50×50×50mm cube of the rock sample. Additionally, pore pressure can be up to 20 MPa and temperature up to 70oC. Six sets of LVDT strain gauges and 24 acoustic transducers can monitor all deformations and crack events during fracturing of a sample. Through a hole in the center of the rock, a fluid can be injected to simulate hydraulic fracturing, or investigate fault reactivation during fluid injection. All of events are monitored in real-time manner using ultrasonic seismic transducers around the sample. Further details of this equipment are explained in this paper.