Study on mechanical properties and constitutive model of rock-like
materials under acid corrosion
Abstract
Mechanical specimens of rock-like materials were prepared from cement,
gypsum, quartz sand and water. After the specimens were formed, they
were immersed in acid solutions of pH=2 and pH=4 for 60d and 90d
respectively, and uniaxial compression tests were carried out before and
after immersion to obtain mechanical parameters.Quantification of the
extent of degradation of mechanical parameters and introduction of acid
corrosion damage variables.Based on the Lemaitre strain equivalence
principle, the Weibull distribution statistical damage model for
rock-like micro-fractures was combined with a correction for damage
variables that takes into account the effect of residual strength to
derive a damage constitutive model under acid corrosion.The theoretical
damage constitutive curves were compared with the experimental curves to
analyse the applicability of the constitutive equation.The results show
that after corrosion by the acid solution, the initial
compression-density portion of the stress-strain curve of the specimen
becomes longer and the elastic deformation phase becomes shorter,the
elastic modulus, peak stress and residual strength of the specimen all
decrease, and the final strain of the compression-density portion, final
elastic strain, peak strain and residual strength strain values all
increase,the longer the maintenance time and the more acidic the
solution, the more significant the above characteristics are.Comparing
the theoretical and experimental curves, the damage constitutive model,
which includes acid damage and residual strength corrections, agrees
well in the elastic, plastic and post-peak phases.