The role of polyurethane foam compressible layer in the mechanical behaviour of multi-layer yielding supports for deep soft rock tunnels  

作　　者：Haibo Wang Fuming Wang Chengchao Guo Lei Qin Jun Liu Tongming Qu 

机构地区：[1]School of Civil Engineering,Sun Yat-sen University,Guangzhou,510275,China [2]Southern Marine Science and Engineering Guangdong Laboratory,Zhuhai,519000,China [3]Guangdong Key Laboratory of Oceanic Civil Engineering,Zhuhai,519082,China [4]Guangdong Research Center for Underground Space Exploitation Technology,Guangzhou,510275,China [5]Southern Institute of Infrastructure Testing and Rehabilitation Technology,Huizhou,516029,China [6]Department of Hydraulic Engineering,School of Infrastructure Engineering,Dalian University of Technology,Dalian,116024,China [7]Department of Civil and Environmental Engineering,Hong Kong University of Science and Technology,Clearwater Bay,Kowloon,Hong Kong,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2024年第11期4554-4569,共16页岩石力学与岩土工程学报（英文）

基　　金：supported by the National Key Research and Development Program of China (Grant No.2021YFB2600800);the National Key Research and Development 451 Program of China (Grant No.2021YFC3100803);the Guangdong Innovative and Entrepreneurial Research Team Program (Grant No.2016ZT06N340).

摘　　要：The polyurethane foam(PU)compressible layer is a viable solution to the problem of damage to the secondary lining in squeezing tunnels.Nevertheless,the mechanical behaviour of the multi-layer yielding supports has not been thoroughly investigated.To fill this gap,large-scale model tests were conducted in this study.The synergistic load-bearing mechanics were analyzed using the convergenceconfinement method.Two types of multi-layer yielding supports with different thicknesses(2.5 cm,3.75 cm and 5 cm)of PU compressible layers were investigated respectively.Digital image correlation(DIC)analysis and acoustic emission(AE)techniques were used for detecting the deformation fields and damage evolution of the multi-layer yielding supports in real-time.Results indicated that the loaddisplacement relationship of the multi-layer yielding supports could be divided into the crack initiation,crack propagation,strain-hardening,and failure stages.Compared with those of the stiff support,the toughness,deformability and ultimate load of the yielding supports were increased by an average of 225%,61%and 32%,respectively.Additionally,the PU compressible layer is positioned between two primary linings to allow the yielding support to have greater mechanical properties.The analysis of the synergistic bearing effect suggested that the thickness of PU compressible layer and its location significantly affect the mechanical properties of the yielding supports.The use of yielding supports with a compressible layer positioned between the primary and secondary linings is recommended to mitigate the effects of high geo-stress in squeezing tunnels.

关 键 词：Multi-layer yielding supports Polyurethane foam compressible layer Synergistic mechanism Large-scale model test Deep soft rock tunnels 

分 类 号：TU43[建筑科学—岩土工程]