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Centrifugal Model Test on Long-term Settlement of Shield Tunnels in Soft Soils
（1 Foshan Railway Investment Construction Group Co., Ltd, Foshan 528000; 2 Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety, Key Laboratory of Road and Traffic Engineering of Ministry of Education, Shanghai 201804）
Abstract Large settlement or differential settlement of shield tunnels built in soft soils occurs in long-term service,affecting performance of segment structure and operating safety. On the background of Foshan metro line 3, this article studied the development law of medium and long-term settlement of shield tunnels in soft soils with different thicknesses and the influence of subsoil reinforcement on long-term settlement by centrifugal model test. The results indicate that the worse and thicker the underlying stratum of tunnel is, the larger the long-term settlement is,and the longer the long-term settlement development is. At the same time, long-term settlement increases under large buried depth; long-term tunnel settlement and ground surface deformation decrease with an increase of foundation soil reinforcement depth, but the decrease extent reduces gradually, and the long-term settlement decreases by 16.7%, 30.2% and 41.3% respectively when the reinforcement depths of foundation soil are 3 m, 6 m and beyond the soft soil, and the ground surface deformation right above the tunnel decreases by 25.4%, 44.9% and 66.3% respectively
Abstract：
Large settlement or differential settlement of shield tunnels built in soft soils occurs in long-term service,affecting performance of segment structure and operating safety. On the background of Foshan metro line 3, this article studied the development law of medium and long-term settlement of shield tunnels in soft soils with different thicknesses and the influence of subsoil reinforcement on long-term settlement by centrifugal model test. The results indicate that the worse and thicker the underlying stratum of tunnel is, the larger the long-term settlement is,and the longer the long-term settlement development is. At the same time, long-term settlement increases under large buried depth; long-term tunnel settlement and ground surface deformation decrease with an increase of foundation soil reinforcement depth, but the decrease extent reduces gradually, and the long-term settlement decreases by 16.7%, 30.2% and 41.3% respectively when the reinforcement depths of foundation soil are 3 m, 6 m and beyond the soft soil, and the ground surface deformation right above the tunnel decreases by 25.4%, 44.9% and 66.3% respectively
ZHU Jianfeng1 GONG Quanmei2
.Centrifugal Model Test on Long-term Settlement of Shield Tunnels in Soft Soils[J] MODERN TUNNELLING TECHNOLOGY, 2019,V56(4): 49-55
2019, Vol. 56 