1. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China;
2. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China
Abstract： The design of shield tunnels still mainly depends on experience to choose design parameters, then check the structure safety, which results in the difficulty to consider the relationship between cost and control indicators (tunnel convergence deformation, etc. ) quantitatively. Takes lining thickness, steel reinforcement ratio, bolt diameter of circumferential joints as design parameters, costs and lateral convergence deformation of the tunnel as optimization targets, and combines the principle algorithm of multi-objective optimization to design the shield tunnel. Based on the NSGA-Ⅱ algorithm, the non-dominated principle is used to deal with the complex constraints, which is realized by adopting a constraint violation function. Finally, an illustrative example is introduced and the complete Pareto front is obtained while the safety constraints are satisfied. Then the difference of the result between constraint and unconstraint situations is analyzed, the convergence of the iterative process is expressed, then the value of Pareto front is discussed and the optimal solutions in different conditions are listed and compared.
