Effects of Vegetation Recovery on Topsoil Compressibility and Load Support Capacity of Typical Black Soil
To explore the changes of black soil' s compressibility and load support capacity in the restoration process,we took the topsoil (0-10 cm) in typical black soil region with vegetation restoration of 14,36 and 50 years and the nearby farmland as test objects.We used fast oedometer test to measure and calculate soil mechanical parameters,soil void ratio,the compression index and the pre-compression stress.The soil void ratio,compression index,and pre-compression stress were increased with the increasing year of vegetation restoration.The values of compression index and pre-compression stress were varied in 0.231-0.399,4.2-100.00 kPa,respectively.The compression index and pre-compression stress of soils at different age larch plantations were significantly higher than those of tillage soil (p＜0.05),that is,the compression index,pre-compression stress and the tilth of soil were increased with the increasing of recovery years.The soil bulk density,clay proportion decreased and the mass fraction of organic matter were increased with the increasing of recovery years,and good linear regressions were between bulk density,clay proportion,the contents of organic matter and soil mechanical properties.Bulk density had a negative influence on compression index (p＜0.05),the correlation between the contents of organic matter,clay proportion and compression index were closer (p＜0.01).Clay proportion also had a negative influence on precompression stress (p＜0.01).Therefore,degree of soil compaction decrease,soil compressibility and load support capacity were increased with the increasing of recovery years.The conceivable reasons for increasing the soil compressibility and load support capacity were the decrease of soil bulk density,clay proportion and the increase of the content of organic matter due to the vegetation recovery.
Vegetation recoveryBlack soilSoilSoil compressibilitySoil load support capacity
NETL
NSTL
万方数据
维普
