Abstract: Soil arching has a notable influence on the behavior of piled reinforced embankment for its mechanically complex nature. A series of 3D model tests are conducted to explore the influence of the pile-soil relative displacement, embankment height, pile-cap spacing and horizontal reinforcement tension strength on the stress concentration ratio as well as the embankment settlement. The test results show that: soil arching is closely related to the pile-soil relative displacement and there exists a critical pile-soil relative displacement of approximate 6 to 8 mm which makes the stress concentration ratio reaching its maximum value. The bigger the ratio of embankment height is to the pile-cap clear spacing, the bigger the stress concentration ratio and the smaller the differential settlement on the surface of the embankment are; a bigger ratio of the cap width to the pile-cap clear spacing will result in a bigger stress concentration ratio and a smaller differential settlement. The installation of horizontal reinforcement within the embankment will effectively increase the stress concentration ratio and decrease the surface settlement; a low embankment as well as high tension strength of the reinforcement will enhance the function of the horizontal reinforcement. The equal settlement plane height is about 3.5 times the pile-cap clear spacing for 3D soil arch in piled reinforced embankments.

Key words: piled reinforced embankment, 3D soil arching, model test, soil stress concentration ratio, equal settlement plane