温度对崩壁红土层土壤干缩裂隙形态影响的定量研究

Quantitative Study on the Effect of Temperature on the Formation of Soil Desiccation Cracks in Red Soil Layer in Benggang Areas

  • 摘要:
      目的  探究干燥温度对土壤水分的蒸发速率及其崩壁土壤干缩裂隙的发育过程的影响,为准确认识崩壁土壤裂隙的形态及其对揭示崩岗的发展过程提供理论依据。
      方法  研究选取典型崩岗区崩壁的红土层土壤,模拟干缩裂隙发育过程,通过图像处理技术,定量分析裂隙表面参数,探讨温度对崩壁红土层土壤裂隙发育的影响。
      结果  温度降低,土壤水分蒸发速率下降,裂隙面积和裂隙总长度增大,裂隙率提高,同时块区面积降低,块区个数以及裂隙条数、节点数显著增加,整个土体呈现出越发破碎的状态。由于裂隙条数的显著增加,低温状态下(40 ℃)裂隙的平均长度小于高温条件(80 ℃)的试样,即低温条件较高温条件土壤裂隙发育数量更多,平均长度更小;土壤裂隙的平均宽度随温度升高呈现增大的趋势;分形维数随着温度的降低呈现增大的趋势。黏粒含量显著影响土壤干缩裂隙发育的温度效应。
      结论  在较低温度条件下,崩壁红土层表层土壤水分蒸发时间长,裂隙发育过程更缓慢,但发育程度高,裂隙结构更复杂。

     

    Abstract:
      Objective  It is of great significance to accurately understand the morphology of soil cracks in Benggang wall to reveal the development process of Benggang. Desiccation temperature affects the evaporation of soil water as well as the development of soil cracks. However, there is a lack of research on the temperature effect of desiccation cracks in soil of Benggang wall.
      Method  In this study, the soil of red soil layer in typical Benggang area was selected, and the surface parameters of cracks were quantitatively analyzed by image processing technology to explore the influence of temperature on the development of soil cracks in red soil layer of Benggang.
      Result  The results showed that when the temperature decreased, the evaporation rate of soil water decreased, the crack area and the total length of the crack increased, and the crack rate increased. At the same time, the block area decreased, the number of the block, the number of the crack and the number of the joint increased significantly, and the whole soil was more fragmented. Due to the significant increase in the number of cracks, the average length of cracks in soil samples at low temperature (40 ℃) was smaller than that at high temperature (80 ℃), that is, the number of cracks in soil samples at low temperature was more and the average length was smaller than that at high temperature. The average width of soil crack increased with the increase of temperature. The fractal dimension of soil crack increased with decreasing temperature. The temperature effect on soil desiccation crack development was significantly affected by soil clay content.
      Conclusion  The surface soil water evaporation time of red soil layer in the Benggang wall is longer under the condition of lower temperature, and the development process of cracks is slower, but the development degree is higher, and the crack structure is more complex.

     

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