Abstract
Novel roadbed that laminates one lime-fly ash layer between two sand layers, i. e. laminated roadbed and the roadbed replaced with sand were executed as preventive measures against mud-pumping. And after the execution, various long term observations were carried out to investigate the effect of improvement as produced by these preventive measures. In addition, numerical calculations considering maturity expressed by temperature and elapsed day were performed to evaluate the influence of temperature on coefficients of subgrade reaction of laminated roadbed.
It was found that laminated roadbed had enough stability against train load and the tendency in increasing was clearly different by time of execution, although the calculated bearing capacity of laminated roadbed increased with elapsed day.
