模拟农业机械对土壤压实的试验研究

目的]进行模拟农业机械对土壤压实的实验,为研究农业机械对土壤造成的压实破坏提供理论依据。方法]重塑含水率(级差为3%)和体积密度(级差为0.2 g/cm3)不同的水稻土和黄棕壤,利用土壤固结仪对其进行模拟压实,分析压实对土壤容重、饱和持水率和应力传递系数的影响。结果]随着含水率的增加,压实对土壤的影响逐渐加重,且当土壤含水率在16%~22%时压实对土壤产生的破坏较为严重。土壤抗压实能力随体积密度的增加而增加。相同含水率和体积密度土壤应力传递系数不变,即传递至土壤底层应力σz与土壤表面施加力σ0呈相对稳定的线性关系。结论]机械压实会使土壤容重增加,饱和持水率降低。随着土壤含水率的减少和体积密度的增加,压实对土壤的影响减弱。土壤应力传递系数与土壤类型、含水率、体积密度等有关。对于给定状态的土壤,其土壤应力传递系数不变。

Experimental Study on Soil Compaction by Simulated Agricultural Machinery

Objective] The experiment was carried out to simulate the soil compaction of agricultural machinery,and the theoretical basis was provided to study the compaction and failure of soil caused by agricultural machinery.Method] The paddy soils and yellow brown soils with different water content (rank differences:3%) and bulk density (rank difference:0.2 g/cm3) were reconstructed.The soil consolidation was simulated by soil consolidation instrument and analyzed the effects of compaction on soil bulk density,saturated water-holding capacity and stress transfer coefficient.Result] With the increase of water content,the effect of compaction on soil gradually increased,and when soil moisture content was 16%-22%,soil damage was more serious.The compressive capacity of soil increased with the increase of bulk density.The soil moisture transfer coefficient of the same moisture content and bulk density was constant,that was,the linear relationship between the stress σz and the soil surface application force σ0 was relatively stable.Conclusion] Mechanical compaction will increase the soil bulk density and reduce the saturated water-holding capacity.With the decrease of soil moisture content and the increase of bulk density,the effect of compaction on soil becomes weak.Soil stress transfer coefficient is related to soil type,water content,bulk density and so on.For a given state of soil,the soil stress transfer coefficient remains unchanged.