Excavation Face Stability Analysis of a Doubl-Mode Shield
Crossing Soil&nbsp;and Rock Composite Strata Based on Tensile Strength
Cut-off Effect

HUANG Fu; XIAO Hui; WANG Yongtao; ZHANG Min; CHEN Jingjing; FANG Wei

doi:10.3973/j.issn.2096-4498.2025.01.008

2025 , Vol. 45 >Issue 1: 109 - 119

DOI: https://doi.org/10.3973/j.issn.2096-4498.2025.01.008

Excavation Face Stability Analysis of a Doubl-Mode Shield Crossing Soil and Rock Composite Strata Based on Tensile Strength Cut-off Effect

HUANG Fu ,
XIAO Hui ,
WANG Yongtao ,
ZHANG Min ,
CHEN Jingjing ,
FANG Wei

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(1. School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, Hunan, China; 2. School of Traffic & Transportation, Changsha University of Science & Technology, Changsha 410114, Hunan, China)

Online published: 2025-01-20

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Abstract

Existing studies on the stability analysis of excavation faces for double-mode shields do not consider the tensile strength cut-off effect, making it challenging to accurately reflect the actual failure characteristics of soils ahead of the excavation face; to address this, a three-dimensional failure mechanism for the excavation face of a double-mode shield crossing soil and rock composite strata is constructed using a spatial discretization technique that incorporates the tensile strength cut-off effect. The internal and external energy consumption power equations for this mechanism are derived, and the objective function of the support pressure for the double-mode shield excavation face is established. The optimal support pressure for the excavation face of a double-mode shield at the soil and rock interface is determined through optimal computation. A numerical simulation technique also calculates the ultimate support pressure required to maintain excavation face stability. The results indicate the following: (1) The support pressure considering the tensile strength cutoff effect is greater than that without this consideration, and the support pressure decreases as the tensile strength reduction factor increases. (2) A comparison between the support pressure obtained from the numerical simulation technique and that derived from the theoretical method validates the effectiveness of the proposed theoretical method.

Key words： soil and rock interface; three-dimensional failure mechanism; excavation face support pressure; tensile strength cut-off effect; double-mode shield

Cite this article

HUANG Fu , XIAO Hui , WANG Yongtao , ZHANG Min , CHEN Jingjing , FANG Wei .

Excavation Face Stability Analysis of a Doubl-Mode Shield Crossing Soil and Rock Composite Strata Based on Tensile Strength Cut-off Effect

[J]. Tunnel Construction, 2025 , 45(1) : 109 -119 . DOI: 10.3973/j.issn.2096-4498.2025.01.008

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