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西南喀斯特地区的石漠化已经严重影响了人民正常的生产生活。水土流失是石漠化过程中一个关键环节。喀斯特地区地表广泛覆盖的红粘土在降雨条件下随着含水量的增加和人工垦殖的影响,剪切强度会产生变化,更易发生水土流失。本文以贵州普定石漠化研究区(陈旗村)的红粘土为例,以原状土模拟未经扰动的土样,以重塑土来模拟经过开垦被扰动后的土样,设计了原状土和重塑土在不同含水量下的直剪试验,初步地研究了这一变化规律。结果表明:在含水量大于35%时,石漠化地区红粘土粘聚力和内摩擦角均随着含水量的增加显著降低;在同一含水量水平下,原状土的抗剪强度明显优于重塑土,且随着含水量的增加,重塑土的强度衰减较之原状土快许多,表明了经过人工垦殖后的红粘土在降雨条件下更易发生水土流失。
Rocky desertification in the karst area of southwest China has seriously affected the people’s normal production and life. Soil erosion is a key link in the process of rocky desertification. With the increase of water content and artificial reclamation under the condition of rainfall, the shear strength of red clay widely covered in the surface of karst area will change and soil erosion will be more prone to occur. Taking the red clay of the research area of rocky desertification (Chenqi Village) in Puding county of Guizhou Province as an example, the undisturbed soil samples were simulated by undisturbed soil to remolding the soil to simulate the disturbed soil samples after reclamation, And remolded soil under different water content of the direct shear test, preliminary study of this change. The results show that the cohesion and internal friction angle of red clay in the rocky desertification area decrease significantly with the increase of water content when the water content is more than 35%. Under the same water content, the shear strength of undisturbed soil is obviously better than Remodeling of soil, and with the increase of water content, the intensity of remolded soil decays much faster than that of undisturbed soil, indicating that red clay after artificial cultivation is more prone to water and soil loss under rainfall.