Tensile Strength and Deformational Behavior of Stylolites and Mineral Healed Joints Subject to Dynamic Direct Tension

Some rock discontinuities, such as bedding planes, incipient and healed joints, can sustain significant tension. Rock masses are often subjected to dynamic loadings. However, the ways in which dynamic tension affects the properties of rock discontinuities remain poorly understood. To investigate the tensile response of rock discontinuities under high strain rates, direct tension tests using the split Hopkinson tension bar were conducted on natural limestones with discontinuities including stylolitic joints and mineral healed joints. The results demonstrate that the dynamic tensile strengths of these joints increase with increasing strain rate, and a nonlinear empirical relationship is proposed to capture these effects. In addition, the dynamic tensile stress sustained by the discontinuity shows a nonlinear relationship with its opening (i.e., displacement of the discontinuity under tension). The critical joint opening increases almost linearly with increasing strain rates. The findings of this study can enhance the understanding of the behavior of rock discontinuities under dynamic tension, and facilitate dynamic and seismic analyses for various rock engineering problems.