Deformation–stress performance of anti-seepage structure in soil foundation with spatial variability of mechanical parameters based on SRM and PDEM

Purpose The deformation–stress state of anti-seepage structure in soil foundation is crucial to the safety evaluation of earth-rock dam, and the mechanical parameters of overburden are important factors. However, the long-term sedimentary soil exhibits both discontinuity in lithology and spatial variability of mechanical parameters, which have received less attention in the existing research. The purpose of this paper is to investigate the influence of spatial variability of the overburden to obtain a more accurate safety performance of anti-seepage structure. Design/methodology/approach The random field for overburden mechanical parameters is constructed and analyzed based on the spectral representation method (SRM) combined with the probability density evolution method (PDEM). The effective simulation range of spatial variability was studied firstly. The deformation–stress response of the anti-seepage structure was investigated in detail while taking into account the spatial variability of strength and modulus of overburden. Findings The simulation range of spatial variability can be reduced to 1.2 times overburden thickness on both sides of anti-seepage structure. The deviation for this simulation range is less than 5% to the whole overburden range, but the efficiency of random fields generation is improved by over 70%. The safety performance of anti-seepage structures is overestimated when spatial variability is ignored in traditional methods. Compared with the spatial variability of modulus, the strength has a stronger influence on the safety performance of anti-seepage structure. Originality/value This study presents a strategy for simulating the spatial variability of mechanical parameters of overburden and provides theoretical and technical support for the safety evaluation of anti-seepage structures.