LABORATORY TESTS ON DYNAMIC MODULUS AND DAMPING RATIO OF CEMENT-STABILIZED EXPANSIVE SOIL AS SUBGRADE FILLING OF HEAVY HAUL RAILWAY

Dynamic elastic modulus and damping ratio are important mechanical parameters in soil dynamics analysis. Considering the characteristics of heavy-duty railway loads, the dynamic modulus and damping ratio of cement-stabilized expansive soil are less. Based on the background of the railway coal transportation channel(hereinafter referred to as Meng-Hua Railway) in the central area of the city of Tolemon and the central China, the dynamic modulus and damping ratio of 3% and 5%cement reinforced expansive soils were studied and compared with the expanded soil from Dashanzhai expansive soil in Dengzhou City, Nanyang, under the consolidation with different frequencies, confining pressure, ratio and dynamic stress amplitude. The results were compared with expansive soils. The results show that the maximum dynamic modulus of cement modified with 3% and 5%modified expansive soil is about 3-4 times that of expansive soil. When the dynamic strain is less than 0.002, the dynamic elastic modulus has a steep drop and decreases by 70%. In the dynamic elastic modulus-strain curve, when the dynamic strain is greater than 0.002, the decrease is small, and the dynamic elastic modulus tends to be stable with the dynamic strain. The dynamic elastic modulus increases as the confining pressure, the frequency and the cement content increase. Damping ratio decreases as the confining pressure and consolidation ratio increase. At low strain levels, the consolidation ratio is positively correlated with the dynamic modulus. At high strain levels, the consolidation ratio is inversely related to the dynamic modulus. At the same time, the dynamic modulus and damping ratio are normalized and analyzed, and an empirical formula for estimating the dynamic modulus and damping ratio is established.