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Geomechanics and Engineering
  Volume 29, Number 2, April25 2022 , pages 193-205
DOI: https://doi.org/10.12989/gae.2022.29.2.193
 


Visualization analysis of the progressive failure mechanism of tunnel face in transparent clay
Huayang Lei, Saibei Zhai, Yingnan Liu and Rui Jia

 
Abstract
    The face stability of shield tunnelling is the most important control index for safety risk management. Based on the reliability of the transparent clay (TC) model test, a series of TC model tests under different buried depth were conducted to investigate the progressive failure mechanism of tunnel face. The support pressure was divided into the rapid descent stage, the slow descent stage and the basically stable stage with company of the local failure and integral failure in the internal of the soil during the failure process. The relationship between the support pressure and the soil movement characteristics of each failure stage was defined. The failure occurred from the soil in front of the tunnel face and propagated as the slip zone and the loose zone. The fitted formulas were proposed for the calculation of the failure process. The failure mode in clay was specified as the basin shape with an inverted trapezoid shape for shallow buried and appeared as the basin shape with a teardrop-like shape in deep case. The implications of these findings could help in the safety risk management of the underground construction.
 
Key Words
    failure mechanism; soil deformation; transparent clay; tunnel face
 
Address
Huayang Lei and Rui Jia: Department of Civil Engineering, Tianjin University, Tianjin, China 300072;
Key Laboratory of Coast Civil Structure Safety of Education Ministry, Tianjin University, Tianjin, China 300072
Saibei Zhai: Department of Civil Engineering, Tianjin University, Tianjin, China 300072;
Beijing Urban Construction Design & Development Group Co., Ltd., 5 Fuchengmen North Street, Beijing, China 100032
Yingnan Liu: Department of Civil Engineering, Tianjin University, Tianjin, China 300072
 

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