Experiment and Numerical Simulation on Grouting Reinforcement Parameters of Ultra-Shallow Buried Double-Arch Tunnel

For an ultra-shallow buried double-arch tunnel with a large cross-section, the arching effect is difficult to form in surrounding rock, and grouting method often adopted reinforce rock. Hence, examining reinforcement parameters of great significance for potential failure collapse prevention. The land part Haicang undersea was selected as case study; laboratory experiments, theoretical analysis, numerical simulation were performed determine solid strength parameters. effects different water–cement ratios on slurry fluidity, setting time, bleeding rate, sample studied by experiments. A proposed shear grouted rock through grout ratio unconfined compressive mass. Numerical simulations layer thickness ratios. deformation stability law its influence underground pipelines obtained considering spatial excavation reinforcement. reasonable selection range proposed. initial time rate cement increased increasing ratio, while viscosity decreased ratio. determined mass before grouting. When h = 1.5 m suggested η 0.85, surface settlement, vault, nearby pipeline all met design. Moreover, construction requirements more economical. Research results can provide reference similar projects.