基于土粒与含水率变化规律的触土部件黏附特性研究

Adhesion characteristics of soil-touching components based on changing law of particle and moisture of soil

为研究土壤干燥过程中触土部件与土壤之间的黏附特性变化,以16种不同颗粒直径与含水率的湿土壤为试验材料,先进行金属板(65Mn钢)斜坡滑落试验,测量土壤颗粒直径、含水率高低与金属触土部件之间的黏附力大小关系,然后利用显微镜装置观察土壤样品的微观结构以及干燥过程中土壤与金属板的黏附现象。结果显示,含水率为30%、40%的土壤在金属表面上滑落后产生的“痕迹”比含水率为10%、20%的土壤更为明显。其中,含水率30%、颗粒直径10~50μm的土壤具有最大黏附力,在土壤干燥前后,颗粒直径、俯视周长和俯视面积的差异随含水率和颗粒直径的增加而增大;干燥过程中,颗粒之间的间隙逐渐减小,某些颗粒出现“扩散”“收缩”等现象,部分颗粒会发生相对位移,其中30%含水率,颗粒直径为10~50μm的相对位移最大,为13.78μm。随含水率的增加,土壤黏附力先增大后减小;随着颗粒的减小,土壤黏附力逐渐增大,含水率在30%以下,干燥前后颗粒位移量越大,土壤黏附力越强。结果表明,含水率为30%、颗粒直径在10~50μm范围内的土壤表现出最强黏附力,并在干燥过程中呈现出颗粒相对位移最大的现象。

16 kinds of wet soil with different particle diameter and moisture were used to study the changes in adhesion characteristics between soil-touching components and soil during soil drying.The slope sliding test of metal plate(65Mn steel)was conducted to measure the relationship between the particle diameter and moisture of soil and the adhesion between metal soil-touching components.The microstructure of soil samples was analyzed with microscope.The adhesion phenomena between soil and metal plates during the drying process was observed.The results showed that the"traces"produced by soil with a moisture of 30%and 40%sliding on the metal surface were more obvious than those by soil with a moisture of 10%and 20%.Among them,the soil with moisture of 30%and the particle diameter of 10-50μm had the maximum adhesion.The differences in particle diameter,overlooking perimeter,and overlooking area increased with the increase of moisture and particle diameter before and after soil drying.During the drying process,the gap between the particles gradually decreased,some particles had"diffusion","contraction"and other phenomena,some particles occurred relative displacement.The soil with moisture of 30%and the particle diameter of 10-50μm had the maximum relative displacement of 13.78μm.The soil adhesion first increased and then decreased with the increase of moisture.As the particles decreased,the soil adhesion gradually increased.When the moisture was below 30%,the greater the particle displacement before and after drying,the stronger the soil adhesion.It is indicated that the soil with moisture of 30%and particle diameter of 10-50μm exhibits the strongest adhesion and the phenomenon of maximum relative displacement of particles during soil drying.