A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Support on Deformation Failure of Layered Soft Rock Tunnel Under Asymmetric Stress
https://orcid.org/0000-0002-1966-3678
Abstract The Muzhailing tunnel is located in the plateau and mountainous areas. Under the combined action of strong earthquakes, large fault zones and dense and huge tectonic stresses, the weak surrounding rock of the tunnel is usually fissured. Repeated, irregular and asymmetric large deformation and damage accidents often occur during the construction process. To explore the asymmetric large deformation and failure characteristics of the surrounding rock caused by asymmetric stress, this paper considers the equal straight wall arch tunnel as the research object and explores the deformation mechanism of a carbonaceous slate tunnel under asymmetric stress by applying the physical model experiment. Initially, based on the actual geometric characteristics, spatial distribution characteristics and engineering geological conditions of the tunnel, the optimal similarity ratio is determined, and the tunnel physical model under asymmetric stress is established. Afterward, by analyzing the variation laws of displacement, surrounding rock strain anchor cable axial force under asymmetric load, the deformation mechanism of the tunnel surrounded by carbonaceous slate under asymmetric load is revealed. The influence mechanism and control countermeasures of asymmetric stress on the tunnel surrounded by carbonaceous slate are explored by integrating the macro failure characteristics and failure forms of the tunnel. Finally, the 1G-NPR anchor cable characterized by constant resistance and large deformation with a negative Poisson's ratio and the 2G-NPR bolts with long and short combination support are selected to propose control measures for carbonaceous slate tunnels affected by asymmetric stress. The asymmetric support measures are verified by on-site support tools. The research results indicate that with the loading of asymmetrical stress, obvious asymmetrical deformation occurs in the carbonaceous slate tunnel model due to stress concentration, such as bending deformation, block falling and surface peeling of the sidewall and the bottom. The deformation can be effectively controlled by a combination of long and short bolts and cables, which provides a theoretical basis and practical guidance for the design of tunnel asymmetric support with a similar engineering background.
Highlights The failure in the study area represents a parallel or small angle oblique fault mode, leading to severe, non-uniform pressure failure.The sudden increase of the axial force of the monitoring anchor bolt can be used as a monitoring and early warning tool for detecting tunnel deformations.The effect of 2G-NPR large deformation bolt support in controlling asymmetric large deformation failure of tunnel is verified on the geomechanical model experiment and field.
Support on Deformation Failure of Layered Soft Rock Tunnel Under Asymmetric Stress
https://orcid.org/0000-0002-1966-3678
Abstract The Muzhailing tunnel is located in the plateau and mountainous areas. Under the combined action of strong earthquakes, large fault zones and dense and huge tectonic stresses, the weak surrounding rock of the tunnel is usually fissured. Repeated, irregular and asymmetric large deformation and damage accidents often occur during the construction process. To explore the asymmetric large deformation and failure characteristics of the surrounding rock caused by asymmetric stress, this paper considers the equal straight wall arch tunnel as the research object and explores the deformation mechanism of a carbonaceous slate tunnel under asymmetric stress by applying the physical model experiment. Initially, based on the actual geometric characteristics, spatial distribution characteristics and engineering geological conditions of the tunnel, the optimal similarity ratio is determined, and the tunnel physical model under asymmetric stress is established. Afterward, by analyzing the variation laws of displacement, surrounding rock strain anchor cable axial force under asymmetric load, the deformation mechanism of the tunnel surrounded by carbonaceous slate under asymmetric load is revealed. The influence mechanism and control countermeasures of asymmetric stress on the tunnel surrounded by carbonaceous slate are explored by integrating the macro failure characteristics and failure forms of the tunnel. Finally, the 1G-NPR anchor cable characterized by constant resistance and large deformation with a negative Poisson's ratio and the 2G-NPR bolts with long and short combination support are selected to propose control measures for carbonaceous slate tunnels affected by asymmetric stress. The asymmetric support measures are verified by on-site support tools. The research results indicate that with the loading of asymmetrical stress, obvious asymmetrical deformation occurs in the carbonaceous slate tunnel model due to stress concentration, such as bending deformation, block falling and surface peeling of the sidewall and the bottom. The deformation can be effectively controlled by a combination of long and short bolts and cables, which provides a theoretical basis and practical guidance for the design of tunnel asymmetric support with a similar engineering background.
Highlights The failure in the study area represents a parallel or small angle oblique fault mode, leading to severe, non-uniform pressure failure.The sudden increase of the axial force of the monitoring anchor bolt can be used as a monitoring and early warning tool for detecting tunnel deformations.The effect of 2G-NPR large deformation bolt support in controlling asymmetric large deformation failure of tunnel is verified on the geomechanical model experiment and field.
Support on Deformation Failure of Layered Soft Rock Tunnel Under Asymmetric Stress
https://orcid.org/0000-0002-1966-3678
Abstract The Muzhailing tunnel is located in the plateau and mountainous areas. Under the combined action of strong earthquakes, large fault zones and dense and huge tectonic stresses, the weak surrounding rock of the tunnel is usually fissured. Repeated, irregular and asymmetric large deformation and damage accidents often occur during the construction process. To explore the asymmetric large deformation and failure characteristics of the surrounding rock caused by asymmetric stress, this paper considers the equal straight wall arch tunnel as the research object and explores the deformation mechanism of a carbonaceous slate tunnel under asymmetric stress by applying the physical model experiment. Initially, based on the actual geometric characteristics, spatial distribution characteristics and engineering geological conditions of the tunnel, the optimal similarity ratio is determined, and the tunnel physical model under asymmetric stress is established. Afterward, by analyzing the variation laws of displacement, surrounding rock strain anchor cable axial force under asymmetric load, the deformation mechanism of the tunnel surrounded by carbonaceous slate under asymmetric load is revealed. The influence mechanism and control countermeasures of asymmetric stress on the tunnel surrounded by carbonaceous slate are explored by integrating the macro failure characteristics and failure forms of the tunnel. Finally, the 1G-NPR anchor cable characterized by constant resistance and large deformation with a negative Poisson's ratio and the 2G-NPR bolts with long and short combination support are selected to propose control measures for carbonaceous slate tunnels affected by asymmetric stress. The asymmetric support measures are verified by on-site support tools. The research results indicate that with the loading of asymmetrical stress, obvious asymmetrical deformation occurs in the carbonaceous slate tunnel model due to stress concentration, such as bending deformation, block falling and surface peeling of the sidewall and the bottom. The deformation can be effectively controlled by a combination of long and short bolts and cables, which provides a theoretical basis and practical guidance for the design of tunnel asymmetric support with a similar engineering background.
Highlights The failure in the study area represents a parallel or small angle oblique fault mode, leading to severe, non-uniform pressure failure.The sudden increase of the axial force of the monitoring anchor bolt can be used as a monitoring and early warning tool for detecting tunnel deformations.The effect of 2G-NPR large deformation bolt support in controlling asymmetric large deformation failure of tunnel is verified on the geomechanical model experiment and field.
Support on Deformation Failure of Layered Soft Rock Tunnel Under Asymmetric Stress
Yang, Xiaojie (author) / Ming, Wei (author) / Zhang, Weiran (author) / Zhu, Chun (author) / Mao, Yadong (author) / Wang, Xiang (author) / He, Manchao (author) / Tao, Zhigang (author)
2022
Article (Journal)
Electronic Resource
English
BKL:
38.58
Geomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
38.58$jGeomechanik
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB41
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