Investigation on unsaturated soil of mediumcompression settlement prediction

According to the engineering geology conditions of JiaozhouJinan highspeed railway, the ground settlements characteristics with passage of time and the influence of initial saturation of unsaturated soil on consolidation time were examined by observations at site among different construction phases and consolidation tests. Further more, numerical simulation method was introduced to propose optimization reinforcement methods. The results show that settlements during the subgrade filling phase can finish more than 75% of the total settlements, which can be completed more than 90% of the total after a shortterm standing time (about 4 months) under the stage constructed subgrade conditions. The silty clay of lower degree of saturation can shorten the consolidation time than the higher one with continuous gas phase. Different reinforcement methods have different influence on the characteristics of settlements and may be considered in the decision of standing time. The postconstruction settlement can meet the requirement of ballastless track subgrade at least 6 months after construction for the three reinforcement methods introduced.