| dc.description.abstract | Recently, increasing population and urbanization have led to increasing traffic demand. One solution to increase road capacity is to expand the existing roadways by constructing narrow geosynthetic-reinforced soil (NGRS) walls adjacent to previous stable walls. In the case where the space is limited, the construction of GRS walls has to be narrower than the conventional walls. The NGRS walls have an aspect ratio, L/H, (ratio of wall width, L, to wall height, H) less than 0.7 as suggested by FHWA Mechanically Stabilized Earth (MSE) wall design guidelines and placed in front of an existing stable wall (or shored wall). At the upper boundary zone between the reinforced soil and the stable wall, there easily forms a gap, crack, or even trench, triggering ultimate failure (Yang et al. 2008b). However, the interface connections to avoid tension cracks between the existing stable walls and NGRS walls are still not thoroughly investigated. Accordingly, series of dynamic centrifuge modeling tests are conducted to quantitatively investigate the dynamic response of NGRS walls with interface connection under base shaking excitation.
The wall model′s height was 17 cm and carried out under gravitational acceleration 60 g to simulate NGRS walls models with 10.2 m height in prototype scale. The wall models have 0.5 aspect ratio and use polyester and rayon geotextiles as the reinforcement material. The backfill material used in this study is silica sandy soil with 70% relative density. The results from this study indicated that interface connection has the most contribution to the deformation reduction. Connecting the reinforcement to the stable wall leads the independent normalized horizontal displacement [(∆x/H)/g] decreases from 29.2% (unconnected) to be 5.1% (connected). The independent normalized settlement [(∆y/H)/g] decreases from 51.7% (unconnected) to be 12.8% (connected). The narrow GRS wall without interface connection has a significant asymmetric acceleration response due to wall deformation. At the top walls, the outward acceleration response is about 1.9 times larger than the inward. Connecting the narrow GRS wall to the stable wall/slope can efficiently help control the wall deformation significantly in PBA > 0.3 g. Besides, the narrow GRS wall without interface connection still performs well in PBA < 0.3 g. Compared to Rankine′s active earth pressure, in the narrow GRS wall with interface connection to stable face, the left wall (inertia force moves to the inward of the wall) is 3.23 times larger and the right wall (inertia force moves to the outward of the wall) is 1.79 times larger. In the narrow GRS wall without interface connection, the left wall is 3.55 times larger and the right wall is 2.39 times larger. | en_US |