Inducing Tensile Failure of Claystone Through Thermal Pressurization in a Novel Triaxial Device

Complex coupled thermo-hydromechanical (THM) loading paths are expected to occur in clay rocks which serve as host formations for geological radioactive waste repositories. Exothermic packages heat the rock, causing thermal strains and temperature induced pore pressure build-up. The drifts designed such a way limit these effects. One has anticipate failure fracturing of material, should pressures exceed tensile resistance rock. To characterise behaviour Callovo-Oxfordian claystone (COx) under effective tension quantify criterion, laboratory program is carried out this work. THM correspond situ conditions recreated laboratory. end, special triaxial system was developed, allows independent control radial axial stresses, well rock specimens. More importantly, device one maintain on specimen. Saturated cylindrical specimens were tested undrained constrained lateral deformation nearly constant stress. heated until created stresses ultimately fractured material. happened at average around 3.0 MPa. Fracturing different total describe with Hoek–Brown or Fairhurst’s generalized Griffith criterion. Measured extension analysed based transversely isotropic thermo-poroelastic constitutive model, able satisfactorily reproduce observed behaviour.