Abstract: The technological progress, challenges, and innovations on recycling of shield tunnel spoil are presented. First, the classification standards on recycling both in China and abroad are introduced. Four types of recycling technologies for shield tunnel spoil, i.e., shield construction auxiliary materials, recycled building materials, vegetation reclamation materials, and engineering refilling materials, are then elaborated. The challenges in refinement, optimization, scale, and industrialization in terms of standards, methods, equipment, and market benefits of reuse technology are clarified and analyzed. The standardized technical process for resource recycling of shield tunnel spoil is established from preliminary assessment, graded treatment, feasibility evaluation of spoil recycling to performance and market benefit assessment. In addition, the paper highlights the new technologies of shield tunnel spoil reuse as synchronous grouting materials, vegetation reclamation medium, and nonfired building materials. The classification standard for shield tunnel spoil recycling as synchronous grouting materials, multiobjective programming of recycled product performance optimization, the feasibility test method of shield tunnel spoil reuse as vegetation reclamation medium, and the process and parameter optimization for nonfired hollow bricks are proposed. Finally, the technologies and industrial development trend of resource recycling technology for shield tunnel spoil in China are discussed.

Key words: shield tunnel, spoil, resource recycling technology; synchronous grouting material, vegetation reclamation, nonfired brick