黄土-碎石覆盖层毛细阻滞效应及设计厚度分析

发布时间：2018-10-09 21:12

【摘要】：为了研究我国西北地区以黄土和碎石构成的毛细阻滞覆盖层适用性,验证黄土-碎石间的毛细阻滞效应以及覆盖层初步设计厚度,在西安江村沟垃圾填埋场开展黄土-碎石毛细阻滞覆盖层极端降雨实验.实测黄土-碎石毛细阻滞覆盖层的储水能力,验证了黄土-碎石间的毛细阻滞作用,分析西安地区半湿润气候条件下毛细阻滞覆盖层的初步设计厚度.研究结果表明:在黄土层同为1.0m厚的条件下,毛细阻滞型覆盖层与单一型覆盖层相比,总储水量提高了24.9%~31.8%,有效储水量提高了38.2%~48.9%.现场实测黄土-碎石毛细阻滞覆盖层储水量为116.92mm,而按脱湿和吸湿曲线计算理论储水量分别为137.68和88.30mm.与本次降雨实测的存储量相比,分别偏大17.76%和偏小24.42%.对于黏性黄土分别下衬碎石、粗砂和中砂构建的毛细阻滞覆盖层:若采用黄土脱湿曲线计算初步设计厚度为1.06~1.12m,而采用吸湿曲线初步设计厚度为1.22~1.28m.在黄土毛细阻滞覆盖层厚度设计中,若采用脱湿曲线计算偏于危险,而采用吸湿曲线则偏于安全.
[Abstract]:In order to study the applicability of capillary block overlay composed of loess and crushed stone in northwest China, the capillary block effect between loess and gravel and the initial design thickness of overburden are verified. In Xi'an Jiangcugou Landfill, the experiment of loess-gravel capillary blocking overburden extreme rainfall was carried out. The water storage capacity of loess-gravel capillary block overburden was measured to verify the capillary block effect between loess and gravel. The preliminary design thickness of capillary block overburden was analyzed in the semi-humid climate of Xi'an area. The results show that under the same thickness of 1.0 m in the loess layer, the total water storage capacity of the capillary block overburden is increased by 24.910% and 31.8m, and the effective water storage is increased by 38.2% and 48.9%, compared with that of the single layer. Field measurements show that the water storage capacity of loess-gravel capillary block overburden is 116.92 mm, while the theoretical water storage is 137.68 mm and 88.30 mm respectively according to the desiccant and hygroscopic curves. Compared with the actual storage capacity of this rainfall, it is 17.76% and 24.42% smaller, respectively. For clay loess, the capillary block overburden is constructed with gravel, coarse sand and medium sand respectively. If the initial designed thickness of loess desiccant curve is 1.06 ~ 1.12 m, and the initial design thickness of hygroscopic curve is 1.2222 ~ 1.28 m. In the design of the thickness of loess capillary block overburden, if the dehumidification curve is used to calculate the danger, and the moisture absorption curve is safe.
【作者单位】：浙江大学软弱土与环境土工教育部重点实验室;贵州理工学院土木工程学院;
【基金】：国家“973”重点基金研究发展计划资助项目(2012CB719805)
【分类号】：TU444

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