Analysis on Restrictive Effect of Moisture Content upon Compactive Dry Density of Cohesive Soil

The compaction test of cohesive soil is one of the most basic soil mechanics experiments in various types of geotechnical engineering test specifications,the aim of which is to obtain the optimal water content and maximum dry density under a certain compactive effort.The test results could not only be directly used to guide the engineering constructions,but some other mechanical indexes are also obtained with the compaction test results,therefore,it is particularly important to achieve the accurate compaction test results.Here,by using the soil saturation analysis method,the reasonable calculation and analysis are made for a compacted soil whose saturation coefficient is greater than 100%.The results show that the root cause of problems is not to consider the restrictive effect of the water in clayey soil upon the soil dry density.And it is proposed that the percent moisture content has certain limits on the clay dry density,that is,the maximum dry density of clay soil would not exceed the maximum dry density in saturated state of the compacted soil.