Experimental Study On Dynamic Performance Of Cement Stabilized Macadam Bed Under Repeated Freezing And Thawing

In the seasonal frozen soil area,the high-speed railway embankment is subject to repeated freezing and thawing and is prone to uneven settlement and damage.In addition to the long-term dynamic load action of high-speed trains,tumble-slipped of subgrade structures occurs from time to time.This poses a series of challenges for the design and construction of high-speed railway subgrade in seasonal frozen ground areas.In this paper,the base bed of Haqiake special road is taken as the research object,the influence of particle gradation,permeability coefficient and dynamic load on the bed structure of cement stabilized crushed stone is analyzed in depth,and the cement suitable for the surface structure of the bed of the high-speed railway is found.Stabilized gravel ratio.The main findings are as follows:(1)Through the matching of the preferred multiple sets of graded gravels,a certain amount of cement was adding for the freeze-thaw cycle test.It is finding that when the water content and the cement content were fixing,the content of fine-grained soil was the key to affect the frost heave rate.The amount of frost heaving decreased significantly with the increase in the number of fine particles and the permeability coefficient.(2)Dynamic tests on selected cement stabilized macadam with different particle gradations found that the increase in fine-grained soil could significantly increase the strength and stability of the sample.When the cement content is 3%,it is not removing.The sample with fine-grained soil(content 3%)has the highest strength and the smallest accumulated plastic deformation.In addition,as the number of dynamic loads increases,the modulus of resilience of specimens with different gradations decreases with increasing number of vibrations and tends to stabilize after 10,000 loads.The more components of the fine-grained soil,the greater the resilient modulus,the smaller the plastic deformation,and the shorter the time required to stabilize.(3)Considering synthetically,for the non-permeable subgrade bed structure,the graded gravel with the fine-grained soil content not exceeding 3% and mixing with 3% cement can meet the engineering requirements;for the infiltrating subgrade bed,it is selecting to remove 0.1 mm or less.It is more reasonable to use graded crushed stone with 3% cement.