Abstract: In order to study the development of soil arching in the piled embankment, a series of three-dimensional model tests are conducted. The relationships between stress reduction ratio and ground settlement with different pile cap sizes and different geosynthetic reinforcement materials are analyzed in detail. Based on the test results, it is shown that the effect of soil arching develops gradually with differential settlement and it is more significant at large differential settlement. The inclusion of geosynthetic reinforcements reduces the differential settlement and weakens the soil arching effect correspondingly; and the load transfer from soil to pile top is caused by the combination of soil arching effect and tension membrane effect. The finite element sensitivity analyses are also carried out to study the effects of pile spacing, embankment height and other factors which did not included in the model tests. The focus of numerical analysis are laid on the development process of the soil arching effect and an index is proposed to describe the mobilized degree of the soil arching. Based on the test data, the results of the finite element analyses, and the experimental data collected from literature, a hyperbola equation is suggested to describe the relationship between the mobilized degree of the soil arching and the normalized deformation. The given equation can be used to account the development of soil arching with settlement.

Key words: piled embankment, geosynthetic reinforcement, soil arching effect, differential settlement, model test, finite element method