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Research on Reasonable Combination Forms and Mechanical Deformation Characteristics of Double-layer Superimposed Lining in Deep-buried Tunnels under the Action of Far-field Hydrostatic Pressure
(China Railway Liuyuan Group Co., Ltd., Tianjin 300308)
Abstract In regards to the threats to traditional composite lining structure of deep-buried long tunnels caused by groundwater with high water head, this paper studies a double-layer superimposed lining scheme, which adopts the design concept of "dividing the lining structure into two parts and installing two water-proof layers" , to not only overcome the construction difficulties of mass concrete but also address the leakage issue of secondary lining structure. This paper takes the sea-crossing tunnel project of Qingdao metro line 1 as the engineering basis and analyzes the reasonable combination forms and mechanical deformation characteristics of the double-layer superimposed lining through the finite element calculation software ANSYS. The results show that the internal force distribution of the superimposed lining is related to the structural stiffness ratio of the inner and outer lining layers; the greater the stiffness ratio is, the greater the internal force will be, and when the structural stiffness ratio of the inner and outer lining layers is 0.716, the optimal combination of the superimposed lining thickness is tA=0.95 m and tB=0.85 m; the risk ranking of each control section of the tunnel structure is inverted arch > arch foot > vault; under the action of ex? ternal water pressure on the superimposed lining, the deformation of inner and outer lining layers is coordinated with each other, while the deformation of the inverted arch structure is more sensitive to the stiffness ratio and the external water pressure value than that of the vault and sidewalls; the combination form of the superimposed lining is controlled by the structural load-bearing capacity rather than by the deformation; the structural safety of the optimal superimposed lining combination is also controlled by the bearing capacity when the external water pressure is lower than 1.2 MPa.
Abstract：
In regards to the threats to traditional composite lining structure of deep-buried long tunnels caused by groundwater with high water head, this paper studies a double-layer superimposed lining scheme, which adopts the design concept of "dividing the lining structure into two parts and installing two water-proof layers" , to not only overcome the construction difficulties of mass concrete but also address the leakage issue of secondary lining structure. This paper takes the sea-crossing tunnel project of Qingdao metro line 1 as the engineering basis and analyzes the reasonable combination forms and mechanical deformation characteristics of the double-layer superimposed lining through the finite element calculation software ANSYS. The results show that the internal force distribution of the superimposed lining is related to the structural stiffness ratio of the inner and outer lining layers; the greater the stiffness ratio is, the greater the internal force will be, and when the structural stiffness ratio of the inner and outer lining layers is 0.716, the optimal combination of the superimposed lining thickness is tA=0.95 m and tB=0.85 m; the risk ranking of each control section of the tunnel structure is inverted arch > arch foot > vault; under the action of ex? ternal water pressure on the superimposed lining, the deformation of inner and outer lining layers is coordinated with each other, while the deformation of the inverted arch structure is more sensitive to the stiffness ratio and the external water pressure value than that of the vault and sidewalls; the combination form of the superimposed lining is controlled by the structural load-bearing capacity rather than by the deformation; the structural safety of the optimal superimposed lining combination is also controlled by the bearing capacity when the external water pressure is lower than 1.2 MPa.
GAO Xin WANG Wenjuan
.Research on Reasonable Combination Forms and Mechanical Deformation Characteristics of Double-layer Superimposed Lining in Deep-buried Tunnels under the Action of Far-field Hydrostatic Pressure[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(2): 93-102
2021, Vol. 58 