![]() In addition, the unreasonable setting of structural parameters makes the material stress distribution unreasonable, reduces the bearing capacity of the lining structure, and leads to a series of problems such as concrete cracking and excessive deformation of segments ( Guan et al., 2015). At present, there are few water conveyance tunnels with the new composite lining structure of “steel lining-SCC-segment”, and there is a lack of corresponding engineering experience and theoretical research, especially the stress and deformation of each layer lining are still unclear ( Nabipour et al., 2020). Compared with single-layer lining and double-layer lining structures, the new composite lining structure has higher designed internal water pressure, and under the protection of self-compacting concrete lining in the middle layer, the internal steel pipe is not prone to buckling failure ( Gavriilidis and Karamanos, 2019 Yuan and Kyriakides, 2021). Part of the water delivery project with this structure is shown in Figure 1. Facing the construction requirements of large sections, high internal pressure, and complex internal and external loads, part of the project began to try to use the new composite lining structure of “steel lining-self-compacting concrete (SCC)-segment” ( Cao, 2020). Therefore, multi-layer lining structures are usually used in engineering to joint force to improve the overall load-bearing capacity of the structure ( Vogel et al., 2017 Wang et al., 2019 Ding et al., 2020). The water conveyance tunnel structure is not only subjected to external water and soil loads, but also bears large internal water pressure. In order to solve the problem of regional water use, a number of representative shield water conveyance tunnels have been built in China, such as the Pearl River Delta Water Resources Allocation Project ( Yang et al., 2018 Cao, 2020), the Xijiang Water Diversion Project in Guangxi ( Cao, 2020), the South-to-North Water Diversion Project through the Yellow River Tunnel Project ( Chen et al., 2014 Yang et al., 2018a, b) and so on. With the development of regional economy and the difference of population distribution, the problem of water resources distribution is becoming more and more serious. This analysis model and method considering the deformation coordination relationship solves the problem of setting the parameters of the lining structure and has obvious advantages in the calculation of the stress and deformation of the new composite lining water conveyance tunnel structure, which can provide a theoretical basis for related engineering design. In addition, when the thickness of the steel pipe lining is reduced or the internal water pressure is increased, the circumferential stress and radial displacement generated by the inner lining will increase. The larger the elastic modulus of the inner lining material is, the smaller the radial displacement of each lining structure will be, but the circumferential stress of the inner lining will increase. The results show that the radial displacement and circumferential stress of each layer of lining structure decrease with increasing the thickness of the concrete lining. According to the actual project, the rationality of the calculation method is verified by comparing the results of finite element analysis, and the influence of the thickness of intermediate concrete lining and inner lining parameters on the distribution of force transmission among lining layers is further analyzed. ![]() The stress and deformation of each layer of lining are deduced based on the theory of thick-walled cylinders. Each part of the shield assembled lining is regarded as a stressed spring, and a formula for calculating the equivalent elastic modulus of the overall structure at the joint of the lining under partial tension and partial compression is given. ![]() In this paper, the load structure method and the elasticity theory are adopted, the stress analysis model and theoretical calculation method of a new type of composite lining of water conveyance tunnel are given, and the influence law of lining structure parameters is studied. However, there is still no effective analysis model and calculation method for the parameter influence effect of this new composite lining. 2Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing, ChinaĪ new type of composite lining structure consisting of segments, steel pipes, and concrete lining can be adopted in the water conveyance tunnel to bear large internal water pressure. ![]() 1School of Civil Engineering, Nanjing Forestry University, Nanjing, China.
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