晋陕蒙接壤区露天矿不同质地土壤水分运动特征与模拟

Water movement and simulation of different soil textures at open pit mine in Jin-Shan-Meng adjacent region

分析了晋陕蒙接壤区不同质地土壤水分运动规律,为构造一种理想的层状土体提供参考依据。设置沙土、砒砂岩、黄绵土和红黏土4种均质土柱,利用室内土柱自动观测系统测定4种矿区土壤入渗及蒸发过程,结合HYDRUS-1D模型反解土壤水力参数,并利用反解的参数模拟土壤的入渗与蒸发过程。通过湿润峰运移、入渗速率、累积入渗量评价土壤入渗性能,对比蒸发强度和移动能力评价土壤蒸发性能。研究结果表明,不同质地土壤入渗性能与蒸发性能差异较大,入渗性能从大到小排序为:沙土、砒砂岩、黄绵土、红黏土,蒸发性能从大到小排序为:黄绵土、红黏土、沙土、砒砂岩。4种土壤入渗过程模拟结果的Re(相对误差)绝对值都在11.0%以下,R2在0.90以上,沙土、黄绵土、红黏土蒸发过程模拟结果 Re(相对误差)绝对值在6.1%以下,R2在0.94以上,砒砂岩因质地特殊,蒸发过程模拟结果 Re(相对误差)绝对值为14.0%,R2仅为0.44,整体评价利用HYDRUS-1D结合入渗、蒸发过程剖面含水量变化反演土壤水力参数具有较高的精度。不同质地土壤水分运动特征的测定与模拟,对指导露天矿区排土场新土体构筑提供了参考。

In order to understand the theory for constructing an optimal layered soil,the water movement modeling in different soil textures in Jin-Shan-Meng adjacent region was conducted using soil columns. Homogeneous soil columns including sand,feldspathic sandstone,loessal soil and red clay were repacked. An automatic observation system( AOS) had been applied to these columns to determine the soil water content and weight of each column. Water infiltration and soil evaporation was observed by the AOS and simulated by HYDRUS-1D model. The results show that infiltration and evaporation are different among different soil textures. The infiltration rates in descending order are sand,feldspathic sandstone,loessal soil and red clay. The evaporation rates in descending order are loessal soil,red clay,sand and feldspathic sandstone. The infiltration processes and soil water content under infiltration and evaporation were simulated comparable to measurement. According to the results in this study,the layered soils suggested from top to bottom are feldspathic sandstone,sand,loessal soil and red clay. The upper coarse soil and lower fine soil in soil profile is beneficial to rainfall infiltration and reduces soil evaporation. It is very important to guide soil restoration in open-pit mine region.