The space between the lining and the large diameter that has been excavated by the forward part of the shield is filled with a grout so that many phases of the tunneling process can be performed almost completely by machine.

• 盾构前半部分掘出的隧道直径较衬砌后的隧道直径大，其间的缝隙用水泥灌浆填充。这样一来，挖掘中许多工序可几乎完全由机器操作。