Experimental study of suitability of argillaceous siltstone improved soil as filling for subgrade

To study the suitability of the weak to highly argillaceous siltstone as filling for embankment of high speed railway, the argillaceous siltstone was researched through the indoor experiments, the filling dynamic stability, strength and compression characteristics of argillaceous siltstone physical improved soil were studied, and then indexes such as improved soil subgrade stiffness, water stability and deformation were inspected in situ test. To predict the settlement after acceptance of subgrade, a continuous direct data GM(1,1) model was established. The results show that the argillaceous siltstone should be improved that it cannot be used directly as filling for subgrade of high speed railway. The dynamic stability, strength, stiffness and deformation of subgrade filled with improved soft rock can meet the requirements of high speed railway, but improved soil should not be used for soaking embankment. The continuous direct data GM(1,1) model may require the independent variable is not necessarily equal interval, and this model has very high prediction accuracy compared with the equal interval GM(1,1) model and Poisson curve mode.