Based on the relationship among the coefficient of consolidation Cv

effective stress and void ratio

the equations considering the variation of Cv for consolidation under stage continuous loading are derived. According to analytical solutions of the above equations

a formula for settlement calculation under stage continuous loading is obtained. Combined with the construction of Yun-Gui high-speed railway

taking the stage loading of high embankment as the object of study

stage continuous loading oedometer test of intact expansive soil are carried out on geotechnical digital systems (GDS) triaxial apparatus. It is confirmed that the relationship between settlement and time can be fitted with broken line in loading stage and hyperbola in steady stage. The stress-strain curves of expansive soil can be described with ladder. The coefficient of consolidation increases firstly and then decreases with effective stress when ≤ ; however

it decreases continuously as wave while ＞ The calculated values of degree of consolidation are compared with test results. It is found that the degree of consolidation calculated by considering the variation of Cv is more accurate than constant Cv. The formula for settlement calculation under stage continuous loading can be used as a reference method to analyze the relationship between settlement and time of subgrade for high-speed railway.