quantifying young's modulus of mudstone after water immersion: insights from the mechanical properties of micro-mineral compositions

This study proposes a method to accurately assess the macroscopic young's modulus of mudstone after water immersion, leveraging the mechanical properties of microscopic mineral compositions. the young's modulus and corresponding volume fraction of mineral compositions were determined through nanoindentation tests combined with deconvolution data analysis. results indicate that mudstone at the microscopic scale adheres to a “three compositions-two interfaces” model. the young's moduli of the clay matrix, feldspar minerals and quartz in the original sample were 16.1, 64.8, and 149.6 gpa, respectively. the young's moduli of the three compositions of the mudstone after water immersion decrease to 10.1, 52.1, and 148.4 gpa, respectively, and two interface regions were formed. utilizing uniaxial compression simulations on this model enables the determination of the macroscopic young's modulus of mudstone. comparison of simulation results with macroscale measured values of original mudstone samples yielded an average error of less than 13.2%. the young's modulus of mudstone after water immersion obtained from simulation was 19.7 gpa, with a decrease of 15.1% compared to the original sample. this method holds promise for characterizing the mechanical properties of challenging-to-sample soft rocks.