Study Of Soil Wedge Model For3D Soil Arching In Piled Reinforced Embankments

A piled reinforced embankment consisting of embankment fill? single ormulti-layer of geosynthetic reinforcements?piles?caps and foundation soil?is a newtype of embankment. The system has been increasing widely used to constructhighways on soft soils in recent years because it has some distinctive merits such asshorter construction period, unnecessary of preloading and additional excavation, lesstotal settlements and differential settlements. The mechanism of the piled reinforcedembankment is rather complicated and no design method is available for practice.Consequently, a thorough understanding of soil arching mechanism within theembankment is essential for engineering design.In this study, firstly, a series of3D model tests are conducted to explore theinfluence of the pile-soil relative displacement, embankment height, pile-cap spacingand horizontal reinforcement tension strength on the stress concentration ratio as well asthe embankment settlement. The test results indicate that soil arching is closely relatedto the pile-soil relative displacement and there exists a critical pile-soil relativedisplacement which makes the stress concentration ratio reaching its maximum value.It is also indicate that the ratio of embankment height to the pile-cap clear spacing has anotable influence on the pile-soil stress ratio and that the height of the equal settlementplane is largely decided by the pile-cap clear spacing.Then, the experiments were simulated using a finite difference code, FLAC3D. Thesoil pressure and the height of the equal settlement plane were investigated. Thenumerical results show that the height of the equal settlement plane has nearly norelationship with the reinforcement's tensile strengths and the mechanical properties ofembankment fill. However, using the embankment fill with higher internal friction angle can enhance the soil arching.Finally, a soil wedge model for3D soil arching in piled reinforced embankmentswas developed based on the model tests, numerical analyses as well as field tests result.This can be conveniently used to get the soil stress concentration ratios duringembankment filling and thereafter consolidation process.