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Geomechanics and Engineering
  Volume 23, Number 1, October10 2020, pages 1-13
DOI: http://dx.doi.org/10.12989/gae.2020.23.1.001
 


Seismic stability analysis of tunnel face in purely cohesive soil by a pseudo-dynamic approach
Qi Huang, Jin-feng Zou and Ze-hang Qian

 
Abstract
    To give a solution for seismic stability of tunnel faces subjected to earthquake ground shakings, the pseudo-dynamic approach is originally introduced to analyze tunnel face stability in this study. In the light of the upper-bound theorem of limit analysis, an advanced three-dimensional mechanism combined with pseudo-dynamic approach is proposed. Based on this mechanism, the required support pressure on tunnel face can be obtained by equaling external work rates to the internal energy dissipation and implementing an optimization searching procedure related to time. Both time and space feature of seismic waves are properly accounted for in the proposed mechanism. For this reason, the proposed mechanism can better represent the actual influence of seismic motion and has a remarkable advantage in evaluating the effects of vertical seismic acceleration, soil amplification factor, seismic wave period and initial phase difference on tunnel face stability. Furthermore, the pseudo-dynamic approach is compared with the pseudo-static approach. The difference between them is illustrated from a new but understandable perspective. The comparison demonstrates that the pseudo-static approach is a conservative method but still could provide precise enough results as the pseudo-dynamic approach if the value of seismic wavelengths is large or the height of soil structures is small.
 
Key Words
    limit analysis; tunnel face; seismic; pseudo-dynamic; cohesive soils
 
Address
Qi Huang, Jin-feng Zou and Ze-hang Qian: School of Civil Engineering, Central South University, No.22, Shaoshan South Road, Changsha, Hunan Province, People\'s Republic of China
 

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