新疆准东荒漠矿区砾幕层抗风蚀能力研究

Study on wind erosion resistance of gravel curtain layer in desert mining areas of the Eastern Junggar Basin, Xinjiang

  • 摘要: 砾幕层是由土壤结皮和砾石构成的荒漠矿区特有的重要生态屏障,天然砾幕层具有较强的稳定性,然而大规模的开采扰动导致砾幕层受到严重破坏。为探明砾幕层抗风蚀能力,采集准东5大矿区的砾幕层数据,采用遥感分析、风洞和数值试验,获取准东砾幕层的空间分布特征,并以此分析天然砾幕层砾石覆盖特征,揭示砾石覆盖度和覆盖类型对抗风蚀能力的影响规律及机理,以研究土壤结皮的力学特性及其理化性质,阐明二者间的定量关系。结果表明:① 准东地区砾幕层分布广泛,主要分布在五彩湾矿区和大井矿区的北部,受采矿活动的影响,部分区域的砾幕层遭到严重破坏;② 砾石覆盖度与砾幕层抗风蚀能力成正相关,砾石覆盖度增加15%可减少10%~30%的土壤风蚀;砾幕层中小粒径砾石占比与抗风蚀能力成正相关,相比粒径分布,覆盖度对抗风蚀能力的影响更大;③ 砾幕层土壤结皮抗剪强度与土壤理化性质之间存在相关关系,相关系数大小依次为黏粒(0.946) > 有机质(0.894) > 碳酸钙(0.888) > 含水率(0.518) > 粉粒(0.312),黏粒对结皮抗剪强度影响最为显著,而黏粒含量也能通过影响碳酸钙含量(0.7741)和有机质含量(0.7733)间接影响抗剪强度;④准东地势西北低东南高,其土壤性质分布特征与准东地区的地势变化趋势相符。

     

    Abstract: The gravel curtain layer, composed of soil crust and gravel, offers an important ecological barrier in desert mining area. Natural gravel curtain layers exhibit strong stability; however, large-scale mining disturbances have caused severe damage to the gravel curtain layer. This study was intended to reveal the wind erosion resistance of the gravel curtain layer. For this purpose, we collected samples from the gravel curtain layer in 5 mining areas in the Eastern Junggar Basin and conducted remote sensing analysis, wind tunnel experiments, and numerical experiments. The regional distribution features of the gravel curtain layer in the Eastern Junggar Basin were obtained, and the features of gravel cover in the natural the gravel curtain layer in this region were analyzed. We further revealed the law and mechanism of the in-fluence of gravel cover and cover type on wind erosion resistance and studied the mechanical and physico-chemical properties of soil crust, the quantitative relationship between the two was established. Our results showed that: ① The gravel curtain layer was widely distributed in the Eastern Junggar Basin, primarily in the northern parts of the Wucaiwan and Dajing mining areas. However, some regions have been damaged due to mining activities. ② Gravel cover was positively related to wind erosion resistance of the gravel curtain layer. For every increase in gravel cover by 15%, the wind erosion of soil was reduced by 10%−30%. At the same gravel cover of the desert pavement, the proportion of medium- and small-grained gravel was positively correlated to the wind erosion resistance. Compared with particle size distribution, gravel cover had a larger impact on wind erosion resistance. ③ The shear strength of soil crust in the gravel curtain layer was correlated to the physicochemical properties of soil. The physicochemical parameters of soil were ranked as follows in descending order of the correlation coefficient: clay content (0.946) > organic matter (0.894) > calcium carbonate (0.888) > moisture content (0.518) > silt content (0.312). Clay content has the most significant impact on the shear strength of soil crust, and it not only directly affects shear strength but also exerts indirect influence through calcium carbonate (0.7741) and organic matter (0.7733). ④ The terrain of the Eastern Junggar Basin slopes from low in the northwest to high in the southeast, and the distribution pattern of its soil properties is consistent with the topographical gradient of the region.

     

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