Stress–deformation analysis of concrete anti-seepage structure in earth-rock dam on overburden considering spatial variability of geomechanical parameter

Dams are inevitably built on a deep overburden constrained by site conditions. Moreover, the spatial variability of the geomechanical parameter in overburden tends to significantly affect the mechanical state of the dam foundation anti-seepage structure. In this study, random field theory was combined with finite element analysis to consider the spatial variability of geotechnical parameters in the overburden. Gaussian autocorrelation function and spectral representation were used in random field simulations followed by stochastic finite element calculation. Subsequently, the deformation modulus in Duncan-Chang E-B model was selected as a random parameter in combination with an engineering example. The tensile stress at the top of the anti-seepage structure, horizontal displacement at the top of the cutoff wall, and compressive stress of the cutoff wall were analyzed using statistical laws and the probability distribution tests of the mean value, maximum value, exceedance probability, and 95% confidence interval limit. The results show that when the spatial variability of geomechanical parameter in overburden is not considered, the stress and deformation of the anti-seepage structure are underestimated. Probability distribution statistics of the anti-seepage structure were different from those of geomechanical parameters. The horizontal displacement at the top of the cutoff wall demonstrated a stronger sensitivity to the coefficient of variation than to correlation distance. Therefore, numerical simulations considering the spatial variability of geomechanical parameter in overburden can reasonably reflect the stress and deformation of anti-seepage structure.