Abstract: The excavation of 76m long Dabeiyao Metro tunnel had to be stopped because of quicksand at its roof. A high cost freezing scheme was suggested to use after some researches and tests for more than one year. Hereafter the problem was studied by the authors from geoengineering view point. The geological environment and engineering geological properties of saturated silt and fine sand roof are analyzed in this paper. A new microcement grouting technique is developed to stabilize the Dabeiyiao tunnel roof at the quicksand and quicksand disturbed section. Steel tube grouting is used to stabilize the roof at the undisturbed section. monitoring data indicate that the measures are effective for the roof stability control.