Creep behavior and parameter identification & sensitivity analysis of reconstituted mudstone
摘要
The creep behavior of mudstone is a critical mechanical property influencing the long-term stability of engineering structures built in or on mudstone strata. However, obtaining homogeneous, high-quality specimens is challenging due to mudstone’s low strength and water sensitivity, which can cause softening, swelling, and disintegration. To address these issues, similar materials exhibiting properties closely aligned with those of original mudstone were developed using barite powder, river sand, bentonite, iron powder, glycerol, and gypsum. The design was based on similarity theory and laboratory tests. Uniaxial compression, direct shear, and splitting tests were conducted to evaluate the basic mechanical properties. Uniaxial creep tests were performed to investigate the time-dependent deformation behavior. The results showed that the developed similar materials had stable mechanical and creep parameters, with only moderate variability. The adjustable ranges of elastic modulus, uniaxial compressive strength, cohesion, and internal friction angle were 32.2–57.6 MPa, 0.36–0.83 MPa, 6.6–284.64 kPa, and 13.8°-51.3°, respectively. For the Burgers model parameters, the Maxwell elastic modulus ranged from 48.49 to 2,809.73 MPa, while the Kelvin elastic modulus ranged from 22.13 to 113,576.86 MPa. The Maxwell and Kelvin viscosity coefficients varied within 0.53–38,835.23 MPa·h and 17.59–3,954,426.5 MPa·h, respectively. Glycerol content significantly influenced c, E, σc, and ηM, while iron powder content greatly affected EM, EK, and ηK. Iron powder content had the greatest influence on the φ, whereas gypsum content had the least impact on all physical and mechanical properties. These findings can serve as a reference for selecting similar materials for related tests.