It may avoid stopping transportation and polluting city environment to have excavation in the open replaced by shallow-concealed excavation for large scale underground cable tunnel construction.
采用浅埋暗挖法施工地下电缆隧道取代明沟开挖法，可避免阻断交通、污染城市环境。
2
A joint lever is arranged on the joint, and can press the push rod when pulled by a guy cable to open the valve core.