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The East Cycle Railway of Hainan, which connected the two cities of Haikou and Sanya along the east coast line of Hainan Island, has a 308.072km length of the trunk line. It will invest about RMB 19.22 billion Yuan to get the target value for the maximum speed 200km/h. The East Cycle Railway will be a passenger dedicate line, simultaneously it will take account of the intra-city rail transit of Haikou and a little freight transportation. The passenger carrying capacity per year should be 18 million in the near future and 25 million forward. As to the subgrade, the ballastless track was main adopted with the part from Haikou station to Meilan airport station and the section of Lingshui county, in turn, the rest most used the ballasted track. For the distinctive geo-environments, the subgrade stuffing of group A and B would be in short supply seriously since the excavation of cutting or tunnel and the borrow area nearby can be used. What’s more, all the cutting and borrow area main located in the completely weathered region, and moreover, 60% subgrade stuffing would be completely weathered granite, which would be divided into group C or D mostly. As the stuffing of group C and D should be improved for engineering use, in hence, the following will focus on the improving of completely weathered granite stuffing.Combining the survey and design needs, take 50 group subgrade filling of the East Cycle Railway of Hainan has studied, physical and mechanical properties has tested. and the classification of the subgrade filling, choice of 10 D group with high liquid limit mixed with lime improved subgrade filling, lime dosage respectively is 5%,7%,9%, Another choice of 10 C group with low liquid-limit mixed with cement improved subgrade filling, cement dosage respectively is 3%,5%,7%. Study on physical and mechanical properties has improved and before improve, including the maximum dry density, the optimum moisture content, liquid limits and model limits, model index, free expansion ratio, improved unconfined compressive strength and shear index, free swelling ratio, the unconfined compressive strength and shearing strength parameters of improved subgrade filling, through the contrast analysis and summarize, find the physical and mechanical properties of variation. Find out the solution of improved fully weathered granite as subgrade filling:with high liquid limit fully weathered granite with lime to improve, the best lime content is 9%, Low liquid-limit fully weathered granite with cement to improve, the best cement content is 5%.Combined with the improving program, the technical and economic evaluation of completed weathered granite as subgrade filling have been made in the thesisThe research results can be of some help in the design and construction of the East Cycle Railway of Hainan provides basis, solving the problem that A and B group subgrade filling of the East Cycle Railway of Hainan is very little, and achieved very good effect of improved subgrade filling in subsequent construction process.
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