分析4种不同结构层状土水分入渗规律,为晋陕蒙接壤区露天矿排土场建设筛选合适的层状土体。设置沙土、砒砂岩、黄绵土和红黏土4种均质土柱以及黄-沙-红、黄-红-沙、沙-黄-砒、黄-砒-沙4种层状土,借助室内土柱自动观测系统测定矿区土壤的人渗过程,通过入渗速率、累积人渗量、湿润锋运移、剖面含水量变化分析不同结构层状土入渗特征,结合晋陕蒙接壤区自然条件,评价适合排土场建设的层状土体。结果表明:黄-沙-红、沙-黄-砒型层状土在短时间内能储存大量水分,且第三层土体阻水作用强,黄-沙-红型层状土下层红黏土阻水效果尤其显著,这两种层状土体是矿区排土场较理想的新土体结构。但是,黄-红-沙型层状土人渗速率慢,在强降雨条件下不能使水分迅速入渗。黄-砒-沙型层状土湿润锋到达第三层土体后运移速率仍很快,阻水效果差,水分容易渗漏到深层土壤,这两种层状土结构不宜应用到晋陕蒙矿区排土场建设中。最后探讨了HYDRUS-1D对入渗过程的模拟,利用均质土剖面含水量反演土壤水力参数模拟4种层状土的人渗过程,得到较好的模拟效果。本文对4种层状土入渗特征的测定与模拟,对于指导露天矿区排土场新土体构筑有一定的理论和现实意义。
In order to search for an optimal soil layer structure for constructing an earth dumping site for the open-pit mine at the Jin-Shaan-Meng bordering region, an experiment on soil water percolation through 4 soil columns different in soil layer structure, was carried out. The four soil columns were homogeneously packed with Sandy soil, Pi-sha Sandstone, Loessal soil or Red clay, but different in order, that is, Loessal soil-Sandy Soil-Red clay (L-S-R) , Loessal soil-Red clay-Sandy Soil (L-R-S) , Sandy Soil-Loessal soil- Pi-sha Sandstone ( S-L-P ) , and Loessal soil-Pi-sha Sandstone-Sandy Soil ( L-P-S ) . With the aid of an automatic observation system ( AOS ) attached to the columns to monitor variation of soil water content with time, and at the same time, change in water level in the markov bottles and wetting front movement was recorded. Based on infiltration rate, cumulative infiltration, wetting front movement and change in profile water content, water percolation through the soil columns different in soil layer structure was characterized. Taking into consideration the natural conditions of the region, evaluation of the columns was done for one that was optimal for construction of the earth dumping site. Results show that after water flowing into the second layer of the columns, percolation rate continuously decreased. After water flowing into the third soil layer in Columns L-S-R and S-L-P, percolation rate further decreased. When the wetting front got to the interface between the second and the third soil layers in Columns L-S-R, L-R-S, S-L-P and L-P-S within 169.0, 461.1, 88.6 and 229.1 min, respectively, accumulated percolation reached 19.3, 21.3, 17.8 and 19.6 cm, respectively, in the four columns. In the soil columns the wetting front moved through the 3rd layer of soil at a rate, being 0.34, 0.78, 0.34 and 1.07% of the rate at which it went down through the 2nd layer in Columns L-S-R, L-R-S, S-L-P and L-P-S, respectively. In Column L-S-R, the water content monitored by the probe at