Abstract The arch-cover method has been widely promoted and practiced, and extant studies have recognized the arch cover as the key to construction. However, there has been a lack of in-depth research on its mechanical behavior during construction by the arch-cover method. In view of this, based on the standard section of the Xiaogang Station on the west extension of Qingdao Metro Line No. 2, this paper studies the mechanical behavior involved in "doublelayer initial support arch-cover method" during construction by combining numerical simulation and field monitoring, with a focus on the mechanical effect when the temporary vertical bracing is removed. The results show that the double-layer arch-cover system makes full use of the bearing effect of the underlying hard rock and soil body to effectively control the ground settlement and surrounding rock deformation; Before the removal of the vertical bracing,the pressure on the arch is mainly borne by the temporary vertical bracing and the first layer of the arch cover; after the removal, the arch sank again, while the system underwent a stress conversion, and the two layers of the arch cover eventually enter a phase of synergistic work. The findings show that the double-layer arch-cover method meets the requirements of safe construction as verified in the construction of the Xiaogang Station, and makes it possible to realize the rapid and safe construction of the shallow large-span underground structure.
Abstract：
The arch-cover method has been widely promoted and practiced, and extant studies have recognized the arch cover as the key to construction. However, there has been a lack of in-depth research on its mechanical behavior during construction by the arch-cover method. In view of this, based on the standard section of the Xiaogang Station on the west extension of Qingdao Metro Line No. 2, this paper studies the mechanical behavior involved in "doublelayer initial support arch-cover method" during construction by combining numerical simulation and field monitoring, with a focus on the mechanical effect when the temporary vertical bracing is removed. The results show that the double-layer arch-cover system makes full use of the bearing effect of the underlying hard rock and soil body to effectively control the ground settlement and surrounding rock deformation; Before the removal of the vertical bracing,the pressure on the arch is mainly borne by the temporary vertical bracing and the first layer of the arch cover; after the removal, the arch sank again, while the system underwent a stress conversion, and the two layers of the arch cover eventually enter a phase of synergistic work. The findings show that the double-layer arch-cover method meets the requirements of safe construction as verified in the construction of the Xiaogang Station, and makes it possible to realize the rapid and safe construction of the shallow large-span underground structure.
WEI Zhiyuan1 FENG Jimeng2 YU Longping2
.Study on the Mechanical Behavior of the the Double-layer Arch Cover Initial Support during the Construction of Subway Stations by Arch-cover Method[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(3): 265-274
2022, Vol. 59 