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Mechanical Behavior Analysis and Construction Optimization for Inclined Shaft Transitioning to Main Tunnel in Extreme-highly Stressed and Fractured Strata
(1. China Railway Tunnel Group Co., Ltd., Guangzhou 511458; 2. Guangdong Key Laboratory of Intelligent Monitoring and Maintenance of Tunnel Structure, Guangzhou 511458)
Abstract Aiming at the safety issues caused by multiple disturbances and tunnel group effects during the drill and blast construction of large-section tunnel group in highly stressed and fractured strata in the course of the inclined shaft transitioning the main tunnel, this study investigates the mechanical state and degradation process of surrounding rock during tunnel group construction. Taking the construction of the inclined shaft transitioning to the main tunnel of a deeply buried large-section twin-tube TBM tunnel project as an example, the mechanical mechanism and influencing factors of the tunnel group effect in highly stressed and fractured strata are revealed through theoretical analysis of tunnel mechanics. A three-dimensional numerical model of the tunnel group is established to analyze the stress-strain state of the surrounding rock during the excavation process of tunnel group. The results indicate that strengthening the support structure and constructing the advanced support can both reduce the deformation of the surrounding rock, with the advanced support providing better control effect. By optimizing the construction sequences and using the large pipe roof for pre-supporting, the deformation of the surrounding rock can be effectively controlled without changing the support structure parameters, ensuring construction safety.
Abstract：
Aiming at the safety issues caused by multiple disturbances and tunnel group effects during the drill and blast construction of large-section tunnel group in highly stressed and fractured strata in the course of the inclined shaft transitioning the main tunnel, this study investigates the mechanical state and degradation process of surrounding rock during tunnel group construction. Taking the construction of the inclined shaft transitioning to the main tunnel of a deeply buried large-section twin-tube TBM tunnel project as an example, the mechanical mechanism and influencing factors of the tunnel group effect in highly stressed and fractured strata are revealed through theoretical analysis of tunnel mechanics. A three-dimensional numerical model of the tunnel group is established to analyze the stress-strain state of the surrounding rock during the excavation process of tunnel group. The results indicate that strengthening the support structure and constructing the advanced support can both reduce the deformation of the surrounding rock, with the advanced support providing better control effect. By optimizing the construction sequences and using the large pipe roof for pre-supporting, the deformation of the surrounding rock can be effectively controlled without changing the support structure parameters, ensuring construction safety.
.Mechanical Behavior Analysis and Construction Optimization for Inclined Shaft Transitioning to Main Tunnel in Extreme-highly Stressed and Fractured Strata[J] MODERN TUNNELLING TECHNOLOGY, 2024,V61(4): 142-150
2024, Vol. 61 