Multi-crack interaction in limestone subject to stress and flow of chemical solutions

This paper presented a number of experimental results on investigating mechanism of multi-crack interaction in limestone specimens with two or three flaws of different arrangements under the coupled uniaxial compressive stress and chemical solutions NaCl, CaCl2 and NaHCO3 with different ionic concentrations and pH values. The experiments were conducted on a testing system with a microscope and a CCD camera. The process of initiation, propagation and coalescence of cracks under the influence of the chemical corrosion were observed and digitally recorded. Cracking velocity, strength, cracking patterns, initial angle of new cracks and multi-crack interaction mechanism affected by chemical corrosion were also analyzed and compared with air and distilled water cases. The results indicated that the effect of chemical corrosion was quite complicated, depending on chemical ions and their concentrations and pH values, mineral components of rock, geometry and the number of flaws. The results are helpful guidance to establishing a coupling model for mechanical-hydro-chemical behavior of rocks. (C) 2008 Published by Elsevier Ltd.