黔中地区砂页岩坡耕地的土力学性质研究

Study on Soil Mechanics of Shale Slope Farmland in Coal Formation

坡耕地土力学性质是影响坡面水蚀的重要因素之一,土壤紧实度是土壤抗冲性的直观表现,土壤液限含水量、塑性指数是直接表现土壤可蚀性的重要指标。研究煤系地层砂页岩区坡耕地的土力学性质特征,可为砂页岩区坡耕地的侵蚀过程提供参考依据。以煤系地层砂页岩坡耕地为研究对象,分析了土壤紧实度、液限含水量的特征,探讨了农事活动对土力学性质的影响。结果表明:犁底层紧实度(1384.25 kPa)>耕作层紧实度(481.60 kPa);耕作层土壤液限含水量与犁底层液限含水量的差异不显著;犁底层塑性指数与耕作层塑性指数差异不显著。可见耕作活动改变土壤结构,降低土壤紧实度,是造成黔中地区砂页岩坡耕地水土流失增加的主要原因之一。

The mechanical characteristics of slope farmland soil were one of the important factors affected water erosion.Compactness was one of the direct manifestations of soil scour resistance.Liquid limits and plasticity index were important indexes that directly represent soil erodibility.The research on soil mechanical properties of slope farmland in sand shale area of coal measure strata can provide reference for erosion process of slope land in sand shale area.The characteristics of soil compactness and liquid limit are analyzed,and the effect of agricultural activities on soil mechanical properties were discussed.The result showed that the compactness of plow(1384.25 kPa)is higher than that of plough(481.60 kPa).There is no significant difference between the liquid limit of plow pan and that of plough pan,and there is no significant difference between the plasticity index of plow and that of plough.Tillage changed soil structures and reduced soil compactness,which was one of the main reasons for increased soil and water loss of sand shale farmland in central Guizhou province.