Tunnel face stability analysis by the upper-bound finite element method with rigid translatory moving element in heterogeneous clay

Authors

Feng YANG, Key Laboratory of Engineering Structure of Heavy Railway of Ministry of Education, Central South University, Changsha, Hunan 410075, China
Shi-hua HE, School of Civil Engineering, Central South University, Changsha, Hunan 410075, China
Yao-jie WU, School of Civil Engineering, Central South University, Changsha, Hunan 410075, China
Li-yan JI, School of Civil Engineering, Central South University, Changsha, Hunan 410075, China
Jing-jing LUO, School of Civil Engineering, Central South University, Changsha, Hunan 410075, China
Jun-sheng YANG, Key Laboratory of Engineering Structure of Heavy Railway of Ministry of Education, Central South University, Changsha, Hunan 410075, ChinaFollow

Abstract

The upper-bound finite element method with rigid translatory moving elements (UBFEM-RTME) is further improved to optimise its suitability for analysing the stability in heterogeneous clay. The method is applied to investigate the stability of the tunnel face in undrained clay layer subjected to surface surcharge. The variation of stability load ?s /cu0 and the morphological characteristics and discipline of the effective discontinuities mechanism are obtained for various combinations of dimensionless buried depth ratio C/D, dimensionless gravity parameter ?D/cu0 and the heterogeneous parameter ?D/cu0. The results reveal that C/D and ?D/cu0 have a significant effect on ?s /cu0 and failure mechanism. ?D/cu0 has a great influence on ?s /cu0 but has little effect on failure mechanism. Furthermore, the UBFEM-RTME is used to show the changes of mesh failure modes under different mesh parameters such as the number and distribution of effective discontinuities, and the reasons for improving the accuracy of the upper bound solution are also explained. The applicability of UBFEM-RTME in heterogeneous clay, especially the analysis of failure mode under the limit state, is verified in comparison with the existing rigid-block upper-bound limit analysis methods and finite element bound method.

Graphic Abstract

Recommended Citation

YANG, Feng; HE, Shi-hua; WU, Yao-jie; JI, Li-yan; LUO, Jing-jing; and YANG, Jun-sheng (2020) "Tunnel face stability analysis by the upper-bound finite element method with rigid translatory moving element in heterogeneous clay," Rock and Soil Mechanics: Vol. 41: Iss. 4, Article 10.
DOI: 10.16285/j.rsm.2019.5659
Available at: https://rocksoilmech.researchcommons.org/journal/vol41/iss4/10