Research on key technology and process system of square steel tube concrete arch support for TBM tunnel
LUAN Yingcheng
LU Wei
LIANG Bingchen
WU Yilin
YU Liyuan
SUN Zhonghua
WANG Kun
Abstract：To address the challenge of controlling large deformations in squeezing soft rock for-mations in the tunnel excavation using tunnel boring machine(TBM)and to enhance the a-daptability of TBM construction techniques to major engineering hazards,a high-strength sup-port technology utilizing square steel tube concrete arches was introduced.Flange connection joints for the arches with different structural configurations were designed,and the strength,stiffness,and ultimate deformation capacity of joints with different flange designs were com-paratively analyzed.Furthermore,mechanical loading tests were performed on composite structures comprising SSTC arches and shotcrete layers.These tests elucidated the ultimate strength and failure modes of the composite structure under varying arch spacing conditions.Eigenvalue buckling analyses of multi-unit arch assemblies under different spatial constraint conditions were carried out,clarifying the influence mechanism of spatial connection states on the critical buckling strength governing spatial instability.Field implementation trials of the SSTC arches were conducted,the effectiveness of the design scheme in controlling large soft rock deformations was validated.The results demonstrate that:The yield strength and ulti-mate strength of the continuous flange joints are 1.41 and 1.55 times higher,respectively,than those of non-continuous flange joints.Furthermore,the ultimate deformation capacity of the continuous joints is 3.35 times greater than that of the non-continuous joints.The peak load-bearing capacity of the composite support structure exhibites a decreasing trend with in-creasing arch spacing.The fifth-order buckling modes of the arches consistently manifestes as out-of-plane instability.The scope and density of longitudinal connections significantly influ-enced the spatial stability of the multi-unit arch assemblies.Field comparative monitoring re-veales that the maximum stress in conventional H200 steel arches reaches 400 MPa,whereas it is only 150 MPa in the SSTC arches.This indicates that the SSTC arches possess a superior strength reserve capacity and offer enhanced control over surrounding rock deformation.This research provides crucial theoretical and empirical support for the mitigation of large deforma-tion hazards in TBM-excavated tunnels through squeezing soft rock strata.
Keywords：large deformation tunnel of soft rockTBM constructionsquare concrete-filled steel tubular archflange jointcritical instability strength
Publication Date：2025-09-30
Online Publishing Date：2025-10-31(First online date of this platform, not the publication date of the document)
Pages：11( 1112-1122 )