Based on a typical multi-arch tunnel in a freeway, the fast Lagrangian analysis of continua in 3 dimensions(FLAC3D) was used to calculate the surrounding rock deformation of the tunnel under which the effect of underg...Based on a typical multi-arch tunnel in a freeway, the fast Lagrangian analysis of continua in 3 dimensions(FLAC3D) was used to calculate the surrounding rock deformation of the tunnel under which the effect of underground water seepage flow was taken into account or not. The distribution of displacement field around the multi-arch tunnel, which is influenced by the seepage field, was gained. The result indicates that the settlement values of the vault derived from coupling analysis are bigger when considering the seepage flow effect than that not considering. Through the contrast of arch subsidence quantities calculated by two kinds of computation situations, and the comparison between the calculated and measured value of tunnel vault settlement, it is found that the calculated value(5.7-6.0 mm) derived from considering the seepage effect is more close to the measured value(5.8-6.8 mm). Therefore, it is quite necessary to consider the seepage flow effect of the underground water in aquiferous stratum for multi-arch tunnel design.展开更多
The Xiamen Haicang double-arch tunnel has a maximum span of 45.73 m and a minimum burial depth of 5.8 m.A larger deformation or collapse of the tunnel is readily encountered during tunnel excavation.It is therefore ne...The Xiamen Haicang double-arch tunnel has a maximum span of 45.73 m and a minimum burial depth of 5.8 m.A larger deformation or collapse of the tunnel is readily encountered during tunnel excavation.It is therefore necessary to select a construction approach that is suitable for double-arch tunnel projects with an extra-large span.In this study,three construction methods for double-arch tunnels with extra-large spans were numerically simulated.Subsequently,the deformation behavior and stress characteristics of the surrounding rock were obtained and compared.The results showed that the double-side-drift method with temporary vertical support achieves better adaptability in the construction of such tunnels,which can be observed from both the numerical results and in situ monitoring data.In addition,the improved temporary support plays a critical role in controlling the surrounding rock deformation.In addition,the disturbance resulting from the excavation of adjacent drifts was obvious,particularly the disturbance of the surrounding rock caused by the excavation of the middle drift.The present findings can serve as the initial guidelines for the construction of ultra-shallowly buried double-arch tunnels with extra-large spans.展开更多
基金Project(50490274) supported by the National Natural Science Foundation of ChinaProject(200516) supported by Hunan Transportation Science and Technology
文摘Based on a typical multi-arch tunnel in a freeway, the fast Lagrangian analysis of continua in 3 dimensions(FLAC3D) was used to calculate the surrounding rock deformation of the tunnel under which the effect of underground water seepage flow was taken into account or not. The distribution of displacement field around the multi-arch tunnel, which is influenced by the seepage field, was gained. The result indicates that the settlement values of the vault derived from coupling analysis are bigger when considering the seepage flow effect than that not considering. Through the contrast of arch subsidence quantities calculated by two kinds of computation situations, and the comparison between the calculated and measured value of tunnel vault settlement, it is found that the calculated value(5.7-6.0 mm) derived from considering the seepage effect is more close to the measured value(5.8-6.8 mm). Therefore, it is quite necessary to consider the seepage flow effect of the underground water in aquiferous stratum for multi-arch tunnel design.
基金Much of the research presented in this paper was supported by the National Natural Science Foundations of China(Grant Nos.51379112,51422904,40902084,41772298,and 41877239)the Fundamental Research Funds for the Central Universities(No.2018JC044)the Shandong Provincial Natural Science Foundation(No.JQ201513).
文摘The Xiamen Haicang double-arch tunnel has a maximum span of 45.73 m and a minimum burial depth of 5.8 m.A larger deformation or collapse of the tunnel is readily encountered during tunnel excavation.It is therefore necessary to select a construction approach that is suitable for double-arch tunnel projects with an extra-large span.In this study,three construction methods for double-arch tunnels with extra-large spans were numerically simulated.Subsequently,the deformation behavior and stress characteristics of the surrounding rock were obtained and compared.The results showed that the double-side-drift method with temporary vertical support achieves better adaptability in the construction of such tunnels,which can be observed from both the numerical results and in situ monitoring data.In addition,the improved temporary support plays a critical role in controlling the surrounding rock deformation.In addition,the disturbance resulting from the excavation of adjacent drifts was obvious,particularly the disturbance of the surrounding rock caused by the excavation of the middle drift.The present findings can serve as the initial guidelines for the construction of ultra-shallowly buried double-arch tunnels with extra-large spans.
