Analysis on the Factors Affecting the CBR Value of Silt Roadbed

The silt has engineering defects and its CBR value (California bearing ratio) is low while be taken as roadbed filling. In order to analyze the influence of different factors on the CBR value of the silt roadbed, the CBR value is measured by changing silt particle contents, initial water contents, adding different salt and salt contents, changing overload pressure. The influence characteristics of different factors were also analyzed. The specimens were fabricated by heavy compaction criterion and soaked in water for four days. The standard penetration test was used to measure CBR value. The test results show that the CBR value of silt filling become larger as the silt particle content reduced. The initial moisture content has remarkable influence on the CBR value, and the CBR value reaches the maximum with the optimum water content. The different salt and salt content have different effects on the CBR value, and the CBR value reduces to a great extent as the salt content increases. The overload pressure also has great influence on the CBR value, which became larger as the overload pressure increased. The research shows that they are useful methods to improve bearing capacity of silt roadbed by adding sand, controlling the compacted moisture content, reducing the salt content and preloading.