Study On The Compaction Standard For Cohesive Soil In Rainy And Moist Region

With three kinds of cohesive soil distributed widely in Hunan province as the study objects, the paper research systematically on them through experiments. Firstly, compaction tests of soil sample are carried out to get the complete compaction curves in different compactive effort of each soil. And then, in order to obtain the variation laws of cohesive force and interior friction angle along the complete compaction curve when water content changed, the direct shear test was conducted for each soil sample. The variation laws of the CBR value varied with water content and the unsaturated CBR and saturated CBR under heavy compactive effort were revealed according to the saturated CBR and unsaturated CBR test near the optimum water content. Study on compaction standard at home and abroad, and after compared with the void rate method and the degree of compaction control standard on subgrade compaction, it confirmed that the void rate control standard was rational in rainy and moist region. Analyzed the relationship between dry density,degree of compaction,void rate,expansion rate and water-stability, the rational control range of void rate method on subgrade compaction in rainy and moist region was putted forward. With further analyzed data and theory analyzed of the range of void rate method, it confirmed that the control range of void rate standard was Va≤8%. The study showed that the void rate control method is not only simple but also adopted on the compaction control standard in rainy and moist region. The results can offer important references to the subgrade design and construction.