Abstract: Critical issues in shield tunneling, such as prolonged shield shutdowns, excessive grouting volume, high cement content, and the challenges posed by liquefied sandy layers, contribute to the consolidation and wrapping of the shield shell by the mortar, leading to ground uplift, segment floating, and dislocation. A novel mortar removal technology that uses a pile driver to clamp a Larsen steel sheet is proposed. This method vibrates the shield body and effectively loosens mortar caking and soil encrusting the shell. Key findings include the following: (1) The consolidation and wrapping of the shield shell by mortar are partly attributable to the high ground permeability coefficient and cement concentration in the synchronous grout. (2) Frequent shield shutdowns exacerbate mortar consolidation and wrapping. (3) The proposed measures are effective in removing mortar from the shell, and the occurrence of such phenomena can be minimized by enhancing synchronous grouting techniques.

Key words: super-large-diameter shield, mortar consolidation and wrapping, steel sheet pile