Abstract Using the Liangcun tunnel constructed with the CRD method as an example, the surrounding rock deformation and structural internal force characteristics are analyzed for tunnels constructed by the CRD method by installing deformation monitoring points and internal force testing elements. The surrounding rock displacement and stress variation under different excavation sequences are analyzed and compared by numerical simulation of the excavation process for a tunnel constructed using the CRD method. The results show that the CRD method has a great impact on the construction sequence of each construction part, while the magnitude of impact by each construction part on crown settlement are (from high to low): part one, part two, part three and part four. Rock pressure at the internal side of the mountain is larger than that at the outer side, and all the internal force of the steel brace is compressive stress with the maximum axial force located at the haunch. By comparing the deformation differences caused by tunnel excavation and the structural loading features, and based on a numerical analysis, it is concluded that first excavating a partial section at the outside of the mountain has great advantages in terms of surrounding rock deformation, structural stress and safety factors. Thus, the reasonable construction sequence is to first excavate the partial section outside of the mountain with primary support installation and then to excavate the other section inside of the mountain.
Abstract：
Using the Liangcun tunnel constructed with the CRD method as an example, the surrounding rock deformation and structural internal force characteristics are analyzed for tunnels constructed by the CRD method by installing deformation monitoring points and internal force testing elements. The surrounding rock displacement and stress variation under different excavation sequences are analyzed and compared by numerical simulation of the excavation process for a tunnel constructed using the CRD method. The results show that the CRD method has a great impact on the construction sequence of each construction part, while the magnitude of impact by each construction part on crown settlement are (from high to low): part one, part two, part three and part four. Rock pressure at the internal side of the mountain is larger than that at the outer side, and all the internal force of the steel brace is compressive stress with the maximum axial force located at the haunch. By comparing the deformation differences caused by tunnel excavation and the structural loading features, and based on a numerical analysis, it is concluded that first excavating a partial section at the outside of the mountain has great advantages in terms of surrounding rock deformation, structural stress and safety factors. Thus, the reasonable construction sequence is to first excavate the partial section outside of the mountain with primary support installation and then to excavate the other section inside of the mountain.
SHI ,
XIONG ,
ZHANG Jia-Sheng etc
.A Study of the Construction Sequences of a Large-Section Shallow-Buried Unsymmetrical Loading Tunnel by the CRD Method[J] MODERN TUNNELLING TECHNOLOGY, 2015,V52(3): 193-199
2015, Vol. 52 