Abstract With the gradual increase in awareness of ecological resources protection, the waterproofing type of tun? nels under high water pressure has also been gradually shifting from the "mainly draining" to "fully waterproofing",so resulting in difficulties in mass concrete construction. In view of this, the "double-layer superimposed lining" solution is proposed to reduce the thickness of the structure by "splitting", which can effectively mitigate harmful deformations caused by the cement hydration heat in the structure, and enhance the implementability and operability of mass concrete structure construction, while also improve the quality and effectiveness of tunnel waterproofing.Taking the sea-crossing tunnel section of the Qingdao Metro Line 1 as the engineering background, this paper conducts research of the factors affecting the stability of double-layer superimposed lining by the finite element analysis software ANSYS, and the conclusions are drawn as follows: 1) due to the waterproofing layer between linings, only the radial compression stiffness of the spring can be considered in terms of contact mechanics behaviors of the lining bonding surface, while ignoring the impact of tangential shear stiffness of the spring; 2) when the radial spring stiffness of the bonding surface is of equal order of magnitude to the elastic modulus of the structure at both sides, the safety coefficient curve basically tends to converge, and the structural failure sequences are in the order of the inner lining inverted arch, inner lining arch foot, outer lining inverted arch, outer lining arch foot, inner lining arch vault,outer lining arch vault; 3) the higher the subgrade reaction coefficient of the surrounding rock is, the greater the safety coefficient of the superimposed structure will be, and so attention should be paid to improving the subgrade reaction coefficient of poor surrounding rocks and maintaining that of good surrounding rocks during the design and construction process; 4) the safety coefficient of the superimposed structure increases with the increase of the stiffness of each lining layer, and the inner lining structure has the effect of increasing and improving the safety of the outer lining structure.
Abstract：
With the gradual increase in awareness of ecological resources protection, the waterproofing type of tun? nels under high water pressure has also been gradually shifting from the "mainly draining" to "fully waterproofing",so resulting in difficulties in mass concrete construction. In view of this, the "double-layer superimposed lining" solution is proposed to reduce the thickness of the structure by "splitting", which can effectively mitigate harmful deformations caused by the cement hydration heat in the structure, and enhance the implementability and operability of mass concrete structure construction, while also improve the quality and effectiveness of tunnel waterproofing.Taking the sea-crossing tunnel section of the Qingdao Metro Line 1 as the engineering background, this paper conducts research of the factors affecting the stability of double-layer superimposed lining by the finite element analysis software ANSYS, and the conclusions are drawn as follows: 1) due to the waterproofing layer between linings, only the radial compression stiffness of the spring can be considered in terms of contact mechanics behaviors of the lining bonding surface, while ignoring the impact of tangential shear stiffness of the spring; 2) when the radial spring stiffness of the bonding surface is of equal order of magnitude to the elastic modulus of the structure at both sides, the safety coefficient curve basically tends to converge, and the structural failure sequences are in the order of the inner lining inverted arch, inner lining arch foot, outer lining inverted arch, outer lining arch foot, inner lining arch vault,outer lining arch vault; 3) the higher the subgrade reaction coefficient of the surrounding rock is, the greater the safety coefficient of the superimposed structure will be, and so attention should be paid to improving the subgrade reaction coefficient of poor surrounding rocks and maintaining that of good surrounding rocks during the design and construction process; 4) the safety coefficient of the superimposed structure increases with the increase of the stiffness of each lining layer, and the inner lining structure has the effect of increasing and improving the safety of the outer lining structure.
WANG Wenjuan GAO Xin
.Study on Factors Affecting the Stability of Double-Layer Superimposed Lining#br# in Deep-Buried Tunnels under the Action of High Water Pressure #br#[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(4): 12-20
2021, Vol. 58 