| dc.description.abstract | A series of centrifuge model tests were performed to assess tunneling-induced ground deformations in sandy ground and their effects on adjacent pile foundations. Two topics have been investigated by modeling the ground loss with the way of volume control in this study. First of all, the pile loading test has been analyzed in the different conditions, including the ground loss and the distance between the pile and the tunnel center. Secondly, the load transfer mechanism of the piles has been analyzed in the different conditions, including ground losses, the load on the pile head, and the distance between the pile and the tunnel center.
According to the result in the research, the loss of the ultimate bearing capacity and of the pile end bearing capacity were 60% and 95%, respectively. When the ground loss reached 2% during the pile loading test conducted above the tunnel center. Load transfer behaviors on a pile caused by adjacent tunneling mainly depended on the followed factors: (1) ground loss, (2) the horizontal distance between the pile and the tunnel center, (3)the axial load of the pile head. Ground loss caused by tunneling would affect the distribution of axial force, the skin friction on a pile, and the settlement of pile head. The distribution of axial force along a pile will decrease with decreasing pile point bearing capacity if the ground loss increased. The settlement of pile head will also increase with increasing the ground loss. The increase in the horizontal distance between the pile and the tunnel center will lead to the decrease in the settlement of pile head and the axial force and the skin friction on a pile. The tunneling will not affect the pile if the horizontal distance between the pile and the tunnel center was larger than 10m. When the working load ratio on pile head was 0.5, the soil around the pile will provide the resistance for the pile, and the skin friction along a pile was positive as ground loss occurred; however, that was negative under the condition of 0.3 of working load ratio on the pile. | en_US |