Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Analysis of Tunnel Face Stability of Shield Tunneling Through Water-Rich Sand-Pebble Stratum
The sand and pebble stratum generally exists in the urban underground engineering construction. When disturbed by the outside world, especially under the condition of rich water, it is easy to cause stratum loss due to the characteristics of sand pebble stratum, resulting in instability of the face and surface settlement and other problems. In this paper, the physical and mechanical parameters of sand pebble soil in a subway area of Changsha were obtained through laboratory tests, and then the micro parameters were calibrated. According to the calibrated micro parameters, a PFC3D full scale model considering seepage was established for the stability analysis of the tunnel face. Through the analysis of the numerical simulation results, the influence of different factors such as stress ratio, buried depth (C), shield diameter (D), and boulders on the stability of the tunnel face was obtained, and the variation characteristics of the limit support pressure and the critical stress ratio of the instability index were obtained under different conditions. The results show that the formation stability increases with the increase of stress ratio in the process of shield tunneling. When the stress ratio is less than the critical stress ratio, the tunnel face will be unstable. When the boulder is broken, the instantaneous velocity of the particle in the center of the tunnel surface can reach 3m/s, and the risk of instability of the tunnel surface is increased. The pressure of the limit support increases with the increase of the buried depth. When C/D = 3, the pressure of the limit support tends to be stable. The critical stress ratio decreases with the increase of C/D, and the lower the critical stress ratio is, the stronger the self-stabilizing ability of the tunnel surface is.
Analysis of Tunnel Face Stability of Shield Tunneling Through Water-Rich Sand-Pebble Stratum
The sand and pebble stratum generally exists in the urban underground engineering construction. When disturbed by the outside world, especially under the condition of rich water, it is easy to cause stratum loss due to the characteristics of sand pebble stratum, resulting in instability of the face and surface settlement and other problems. In this paper, the physical and mechanical parameters of sand pebble soil in a subway area of Changsha were obtained through laboratory tests, and then the micro parameters were calibrated. According to the calibrated micro parameters, a PFC3D full scale model considering seepage was established for the stability analysis of the tunnel face. Through the analysis of the numerical simulation results, the influence of different factors such as stress ratio, buried depth (C), shield diameter (D), and boulders on the stability of the tunnel face was obtained, and the variation characteristics of the limit support pressure and the critical stress ratio of the instability index were obtained under different conditions. The results show that the formation stability increases with the increase of stress ratio in the process of shield tunneling. When the stress ratio is less than the critical stress ratio, the tunnel face will be unstable. When the boulder is broken, the instantaneous velocity of the particle in the center of the tunnel surface can reach 3m/s, and the risk of instability of the tunnel surface is increased. The pressure of the limit support increases with the increase of the buried depth. When C/D = 3, the pressure of the limit support tends to be stable. The critical stress ratio decreases with the increase of C/D, and the lower the critical stress ratio is, the stronger the self-stabilizing ability of the tunnel surface is.
Analysis of Tunnel Face Stability of Shield Tunneling Through Water-Rich Sand-Pebble Stratum
Sustain. Civil Infrastruct.
Liu, Yong (Herausgeber:in) / Cuomo, Sabatino (Herausgeber:in) / Yang, Junsheng (Herausgeber:in) / Wang, Wei (Autor:in) / Liu, Fan (Autor:in) / Han, Zhao (Autor:in) / Zhang, Xinyuan (Autor:in) / Zhou, Xu (Autor:in)
Civil Infrastructures Confronting Severe Weathers and Climate Changes Conference ; 2021 ; NanChang, China
24.07.2021
20 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
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