In constructing phase, for extruding shield method, the deformed tunnel lining is like a duck egg standing on end, while for EPB shield, it is like a lying duck egg.

• 在隧道施工阶段,挤压盾构法隧道衬砌呈现“竖鸭蛋”变形,而EPB盾构隧道衬砌则呈现“横鸭蛋”变形。