Abstract:the starting and receiving of Jinhua Road Station Jinshan station section project of Fuzhou Metro Line 5 is located in the water rich sand layer. Steel sleeve is used to deal with the risk of sand and water gushing, and the cutter head is used to cut the glass fiber reinforced concrete wall. At this time, the shield with built-in grouting box equipped with hob cutter head is more convenient to cut and pass through the concrete wall. However, 85% of the bottom of the tunnel in this section is in the extremely soft silt stratum of 45kpa, which will cause the machine head to fall down and the shield attitude to be difficult to control. At this time, the soft soil scraper cutter head should be selected as light as possible instead of the compound hob head which is twice as heavy. At the same time, the shield outside the grouting box has a smaller diameter. Because the gap between the cutter head and the shield body is small, the impact on the surface settlement is relatively small. The problem caused by the outside of the grouting box is how to avoid being stuck by the concrete wall, because once it is stuck, it is very difficult to place. Therefore, in order to meet these two contradictory needs, we have carried out the cutter head selection and anti jamming design when crossing the wall.
