A deep open-cut excavation with three types of continuous retaining walls

The ventilation station is built in stable diluvial strata. There is a layer of Kanto loam and clay from the surface to a depth of 10 m, followed by a layer of Musashino gravel and Tokyo gravel to a depth of 22 m. The ground underneath the Tokyo gravel layer is the 1st Edogawa sand layer, which is stable diluvial sand, and its N value is more than 100. The 1st Edogawa clay layer lies under the 1st Edogawa sand layer.