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Abstract To study appropriateness of granitic residual soil used as fillings of high-speed railways foundation bed bottom and embankment，the clay mineral composition，fluid plasticity index，CBR value，relationship between cumulative residual strain and loading time and critical dynamic stress，etc. which are for its engineering properties，are firstly studied. According to codes for design of Chinese and Japanese high-speed railway，it shall be improved that granitic residual soil is not used directly as a high-speed railway subgrade filling. Secondly，according to the experience of improved fine-grained soil in Japan and China，and characteristics of granitic residual soil，it will be identified that cement contents are added extra in granitic residual soil used as fillings of high-speed railways foundation bed bottom and embankment. Thirdly，the comparison of the field test data between finite element analysis results of performance of improved granitic residual soil subgrade under cyclic loading is analyzed；the dynamic similarity analysis of performance of improved granitic residual soil subgrade is carried out；the parameters of cyclic loading test are identified for performance of highway. Finally，The dynamic performance and physico-mechanical characteristics of improved granitic residual soil used in subgrade of Wuhan—Guangzhou high-speed railways in Qingyuan region of Guangdong Province are also studied，relying on PMS–500 cyclic loading experimental equipment. The dynamic performance and deformation law of improved granitic residual soil subgrade are analyzed under different cyclic loading with and without soaking. It is shown that the improved granitic residual soil could meet the design requirements for all the dynamic indicators and residual settlement of high-speed railway subgrade being influenced by long-term cyclic loading with and without soaking，and could be used to fill the embankment and subgrade bed of highways．
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Received: 12 November 2010
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2011, Vol. 30 
