Reinforcing Mechanism and Tension Behaviors of Geogrid in Pile-Supported Reinforced Embankment

In order to study the reinforcing mechanism and tension behaviors of the geogrid in pile-supported reinforced embankment under dynamic and static loads, a full-scale model test setup for high-speed railway pile-supported reinforced embankment was built. Eight actors were used to impose loads on the embankment to simulate static loads and trains moving loads on the embankment. Meanwhile, stress cells and fiber Bragg grating (FBG) sensors were used to measure the soil pressure and tensile force of the geogrid. The experiment results show that the loads on the embankment could affect the stability of the soil arching. The soil arching experiences a process from strengthening to weakening during the increment of static loads. There exists an upper limit for the percent of loads undertaken by the pile cap. The geogrid could transfer about 12% static loads to the pile cap and the biggest tensile force of geogrid occurs at the center of embankment when the embankment is subjected to static loads. The tensile force of geogrid changes evidently; for example, the tensile force of the geogrid on the center of pile cap increases about 8% when the embankment is subjected to long-term train moving loads. Hence the design of embankment reinforcement should take the influence of moving loads into account.