@Article{cmes.2021.015208, AUTHOR = {Weiwei Sun, Hongping Min, Jianzhong Chen, Chao Ruan, Yanjun Zhang, Lei Wang}, TITLE = {Numerical Analysis of Three-Layer Deep Tunnel Composite Structure}, JOURNAL = {Computer Modeling in Engineering \& Sciences}, VOLUME = {127}, YEAR = {2021}, NUMBER = {1}, PAGES = {223--239}, URL = {http://www.techscience.com/CMES/v127n1/41959}, ISSN = {1526-1506}, ABSTRACT = {To date, with the increasing attention of countries to urban drainage system, more and more regions around the world have begun to build water conveyance tunnels, sewage pressure deep tunnels and so on. However, the sufficient bearing capacity and corrosion resistance of the structure, which can ensure the actual service life and safety of the tunnel, remain to be further improved. Glass Fiber Reinforced Plastics (GFRP) pipe, with light weight, high strength and corrosion resistance, has the potential to be applied to the deep tunnel structure. This paper proposed a new composite structure of deep tunnel lined with GFRP pipe, which consisted of three layers of concrete segment, cement paste and GFRP pipe. A new pipe-soil spring element model was proposed for the pipe-soil interaction with gaps. Based on the C3D8R solid model and the Combin39 spring model, the finite element numerical analysis of the internal pressure status and external pressure stability of the structure was carried out. Combined with the checking calculation of the theoretical formula, the reliability of the two finite element models was confirmed. A set of numerical analysis methods for the design and optimization of the three-layer structure was established. The results showed that from the internal GFRP pipe to the outer concrete pipe, the pressure decreased from 0.5 to 0.32 MPa, due to the internal pressure was mainly undertaken by the inner GFRP pipe. The allowable buckling pressure of GFRP pipe under the cover of 5 GPa high modulus cement paste was 2.66 MPa. The application of GFRP pipe not only improves the overall performance of the deep tunnel structure but also improves the construction quality and safety. The three-layer structure built in this work is safe and economical.}, DOI = {10.32604/cmes.2021.015208} }