Indirect Tension Tests on Rock—Analytical/Numerical Correction for Material Bimodularity
Many rocks have different deformational properties when loaded in tension and in compression. This property is referred to as bimodularity. The influence of bimodularity on four of the most commonly utilized indirect tension testing methods for measuring the tensile strength of rock is investigated analytically and numerically in this paper. These indirect tension methods include the three-point beam-bending test, the hydraulic extension test, the Brazilian test, and the ring test. It is shown that tensile strengths for rock derived from these tests are overestimated if the normal assumption of equal moduli in tension and compression is made. The actual tensile strength may be determined if the moduli ratio in tension and compression is known.