School of Resources and Environments, Southwest University, Chongqing, China.
School of Engineering and Technology, Southwest University, Chongqing, China.
PLoS One. 2019 May 2;14(5):e0215961. doi: 10.1371/journal.pone.0215961. eCollection 2019.
Soil is a porous, multiphase, and loose medium, which is prone to serious disturbance by the activity of biological livings, accompanied with cracks and macro pores. These phenomena greatly affect the strength of soil and the degradation of land. Two different quantifiable values from X-ray computed tomography (CT) images are usually used to define the disturbance function for soil disturbed state strength: mean density (MD value) and standard deviation (SD value). Two types of disturbance functions are investigated quantitatively by CT-triaxial testing using four samples with different macro-pore sizes (disturbed samples) and one sample without a macro-pore (undisturbed sample). It is found that the shear strength of three disturbed samples with the same macro-pore size is close to each other. As with the shear strength, the SD value and its defined disturbance function have a similar correlation with the cross-sectional area of macro-pore. However, the MD value and its defined disturbance function have no regularity with the macro-pore size. Therefore, the disturbance function expressed in terms of the SD value is deemed more reasonable and appropriate in analyzing the soil disturbed state strength using the quantitative CT morphometry. While, the disturbance function defined by the MD value has often been used to characterize a rock damage.
土壤是一种多孔、多相和松散的介质，容易受到生物活动的严重干扰，伴随着裂缝和宏观孔隙。这些现象极大地影响了土壤的强度和土地的退化。通常使用两种不同的定量 X 射线计算机断层扫描 (CT) 图像值来定义土壤扰动状态强度的干扰函数：平均密度 (MD 值) 和标准偏差 (SD 值)。通过 CT 三轴试验研究了两种类型的干扰函数，使用了四个具有不同宏观孔隙尺寸的样本 (扰动样本) 和一个没有宏观孔隙的样本 (未扰动样本)。结果发现，具有相同宏观孔隙尺寸的三个扰动样本的剪切强度彼此接近。与剪切强度一样，SD 值及其定义的干扰函数与宏观孔隙的截面积具有相似的相关性。然而，MD 值及其定义的干扰函数与宏观孔隙尺寸没有规律。因此，使用定量 CT 形态计量学分析土壤扰动状态强度时，基于 SD 值表示的干扰函数被认为更合理和适当。然而，MD 值定义的干扰函数通常用于描述岩石损伤。
