摘要The fork road of a large section tunnel plays a key role in tunnel construction because of its large cross section, complex force, and challenges to construction. A fork road divides a tunnel into several construction work sections, thereby shortening the construction period of a project and accelerating the tunnel construction progress. The fork road of a mountain tunnel enters the main hole by using the bench expansion method. The end of the incline uses upper and lower benches and is constructed 4.2 m upward from the upper bench to determine the height of the pilot tunnel. The main hole boundary line is excavated to complete the pilot tunnel construction. The main hole adopts the three-bench method with upper, middle, and lower benches of 5.3, 3.59, and 3.31 m, respectively, installed along the import and export directions. The main hole of the sectional area (92.1 m2) is a large cross section tunnel whose high span ratio leads to the poor stability of the surrounding rock and support. Therefore, the main hole should be strengthened in the construction to maintain the stability of the tunnel. By using the ABAQUS finite element software for the numerical analysis of the tunnel, the stress distribution of the surrounding rock after tunnel excavation can be intuitively simulated, which can provide a reasonable basis for tunnel construction. The anchor, steel mesh, lining, grille, and steel frame are constructed according to different surrounding rock grades. The monitoring measurement, which monitors the small changes in the surrounding rock and support, can control the stability of the surrounding rock during excavation and the dynamic information of the supporting structure. The regression analysis of monitoring data can reflect the change rule of the surrounding rock, analyze the displacement rate of each stage, and predict the final displacement value. The monitoring data show that the accumulative deformation range of subsidence and surrounding convergence range from 10 mm to 17 mm. Therefore,,the proposed technology can realize a safe, economic, and efficient construction of fork roads and provide a reference for similar conditions.
Abstract：The fork road of a large section tunnel plays a key role in tunnel construction because of its large cross section, complex force, and challenges to construction. A fork road divides a tunnel into several construction work sections, thereby shortening the construction period of a project and accelerating the tunnel construction progress. The fork road of a mountain tunnel enters the main hole by using the bench expansion method. The end of the incline uses upper and lower benches and is constructed 4.2 m upward from the upper bench to determine the height of the pilot tunnel. The main hole boundary line is excavated to complete the pilot tunnel construction. The main hole adopts the three-bench method with upper, middle, and lower benches of 5.3, 3.59, and 3.31 m, respectively, installed along the import and export directions. The main hole of the sectional area (92.1 m2) is a large cross section tunnel whose high span ratio leads to the poor stability of the surrounding rock and support. Therefore, the main hole should be strengthened in the construction to maintain the stability of the tunnel. By using the ABAQUS finite element software for the numerical analysis of the tunnel, the stress distribution of the surrounding rock after tunnel excavation can be intuitively simulated, which can provide a reasonable basis for tunnel construction. The anchor, steel mesh, lining, grille, and steel frame are constructed according to different surrounding rock grades. The monitoring measurement, which monitors the small changes in the surrounding rock and support, can control the stability of the surrounding rock during excavation and the dynamic information of the supporting structure. The regression analysis of monitoring data can reflect the change rule of the surrounding rock, analyze the displacement rate of each stage, and predict the final displacement value. The monitoring data show that the accumulative deformation range of subsidence and surrounding convergence range from 10 mm to 17 mm. Therefore,,the proposed technology can realize a safe, economic, and efficient construction of fork roads and provide a reference for similar conditions.
基金资助:Supported by the National Natural Science Foundation of China (Nos.51574013,51704094)
通讯作者:
JIAO Hua-zhe
E-mail: jiaohuazhe@126.com
引用本文:
焦华喆, 董腾飞, 陈新明, 陈峰宾, 王金星. Construction Technology and Deformation Law of the Surrounding Rock in the Fork Road of a Large Section Tunnel[J]. Journal of Highway and Transportation Research and Development, 2019, 13(4): 56-63.
JIAO Hua-zhe, DONG Teng-fei, CHEN Xin-ming, CHEN Feng-bin, WANG Jin-xing. Construction Technology and Deformation Law of the Surrounding Rock in the Fork Road of a Large Section Tunnel. Journal of Highway and Transportation Research and Development, 2019, 13(4): 56-63.
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2019, Vol. 13 
