To improve the soil and water stability of expansive soil slopes and reduce the probability of slope failure, novel protection systems based on polymer waterproof coatings (PWC) were used in this study. Herein, three groups of expansive soil slope model tests were designed to investigate the effects of polyester nonwovens and PWC (P-PWC) composite protection system, three-dimensional vegetation network and PWC (T-PWC) composite protection system, and non-protection on the soil and water behavior in the slopes under precipitation–evaporation cycles. The results showed that the moisture change of P-PWC and T-PWC composite protected slopes was significantly smaller than that of bare slope, which reduced the sensitivity of slope moisture to environmental changes and improved its stability. The soil temperature of the slope protected by the P-PWC and T-PWC systems at a depth of 70 cm increased by 5.6℃ and 2.7℃, respectively. Using PWC composite protection systems exhibited better thermal storage performance, which could increase the utilization of shallow geothermal resources. Moreover, the maximum average crack widths of the bare slopes were 7.89 and 3.17 times those of the P-PWC and T-PWC protected slopes, respectively, and the maximum average crack depths were 6.87 and 3 times those of the P-PWC and T-PWC protected slopes, separately. The P-PWC protection system weakened the influence of hydro–thermal coupling on the slopes, inhibited the development of cracks on the slopes, and reduced the soil erosion. The maximum soil erosion of slopes protected by P-PWC and T-PWC systems was 332 and 164 times lower than that of bare slope, respectively. The P-PWC and T-PWC protection systems achieved excellent 相似文献