Study on the Control Law of Surface Deformation in Shield Tunnels in Mudstone Strata with the Clay Shock Construction Method

Ground settlement and deformation caused by shield tunnelling is a critical issue that needs to be addressed during construction. The clay shock construction method is an important measure to control surface settlement and deformation during shield tunnelling. To explore the effect law of the clay shock method on surface settlement and deformation in mudstone strata during shield tunnel construction and its control effect, this study uses Sichuan Normal University station to Jiaozili Flyover station running tunnel section of the Chengdu Metro Line 13 as a case study. The research investigates the impact of the clay shock method on surface deformation when tunnelling through mudstone strata, and indoor tests are conducted to reveal the viscosity variation of clay shock samples with different material ratios. Finally, the clay shock method is applied in the field construction, verifying and analyzing its effectiveness. The results indicate: (1) Filling the shield excavation gap with clay shock slurry has a significant impact on surface settlement, reducing the maximum surface settlement by approximately 23.48%; (2) The soil-towater ratio significantly affects the viscosity of the clay shock slurry. The smaller the soil-to-water ratio, the higher the slurry viscosity, and the additives can regulate the slurry viscosity within a certain range; (3) The field measurement data and research results are consistent (with an error of approximately 10%), and the surface settlement value is within the engineering requirement of -20 mm.