Abstract:During the construction of the right-line shield tunneling section of Jinan Metro, the tunnel will pass under numerous above-ground structures. Due to the complexity of the composite geological conditions, abnormal shield tunneling parameters are observed. To ensure the continuous construction of the shield, it is planned to carry out pneumatic operation to open the chamber for inspection. However, due to insufficient understanding of hydrogeological conditions and inadequate handling measures, the gas tightness test fails to meet the standards. Through summary and analysis, the targeted technical safeguard measures are formulated and implemented, including the air-stop ring clamps for shield segments, the advanced horizontal grouting in the tunnel and the establishment of mud film wall protection. The pneumatic chamber opening inspection, maintenance and cleaning work can be successfully completed, which will enhance the understanding of engineering and technical personnel regarding the complex geological conditions of the spring area and also provide a reference for the development of similar projects in the future.
