目前我国西北地区借鉴北美非湿润地区的方法，采用6个经验公式进行生态型土质覆盖层的厚度设计。但是该方法涉及的参数较多、计算过程繁琐，最重要的是忽略了我国西北地区季风气候与北美非湿润地区湿冷气候对覆盖层厚度的不同要求。为了解决上述问题，基于我国西北地区具有典型的雨-热-植生同期、植被非生长期降水量不超过全年总降水量20%的气候特征，并考虑黄土、粉土田间持水量与植被枯萎点之比K ≥ 1.44的持水特点，提出了适用于我国西北地区填埋场生态型土质覆盖层的厚度设计简化方法。利用Vadose/W数值程序分析了采用简化方法设计的单一黄土覆盖层和黄土-碎石毛细阻滞型覆盖层在最大降水量年的水力响应规律。结果表明：毛细阻滞效应阻碍了水分由黄土层向碎石层的大量运移，致使毛细阻滞型覆盖层的防渗表现优于单一型覆盖层。两种覆盖层的防渗表现均随黄土K值的增加而提高，当K ≥ 1.35时，两种覆盖层均可以满足当地的防渗要求，从而初步验证了本文提出的简化方法的可靠性。该简化方法的提出有助于生态型土质覆盖层在我国西北地区的科学设计以及应用推广。

Currently, the thickness design method for ecological soil covers used in Northwest China is based on the practice of non-humid regions in North America, which is complicated, involves many parameters, and fails to consider the different meteorological conditions between Northwest China and North America. To solve this issue, on the basis of the monsoon climate and the feature that the precipitation during the non-growing period of vegetation shall not exceed 20% of the total annual precipitation in Northwest China, as well as the water retention characteristics of ideal cover soils that the ratio of the field capacity to the wilting point K ≥ 1.44, the thickness design method for ecological soil covers used in Northwest China is simplified. Numerical program Vadose/W is utilized to analyze the hydraulic responses of the loess monolithic cover and the loess-gravel capillary barrier cover designed with the proposed simplified method in the year of maximum precipitation. The results indicate that the capillary barrier effect significantly prevents the migration of water from the loess layer to the gravel layer, resulting in the capillary barrier cover having better anti-seepage performance than the monolithic cover. The anti-seepage performance of the two covers decreases with the decrease in the ratio of the field capacity to the wilting point of the loess (i.e., K). When K ≥ 1.35, the two covers can meet the local anti-seepage requirements, thus preliminarily verifying the reliability of the simplified method proposed in this study. The proposal of the simplified method is conducive to the scientific design and application of ecological soil covers in Northwest China.

国家自然科学基金(42107186)；重庆市自然科学基金(CSTB2023NSCQ-MSX0279)