硬岩地层中盾构机下部爆破脱困技术应用

Application of Lower Blasting Technique of Shield Tunneling Machine in Hard Rock Stratum

广州地铁22号线某区间掘进过程中刀具损坏且检查不及时,导致开挖直径过小,盾壳被岩体包裹无法继续向前掘进,额外增加推力依然无法脱困。常规脱困方案是从开挖范围上半部爆破松动地层,因工程顶部硬岩稳定地层较薄,爆破上部容易导致上部地层塌方,故选择向下半部爆破,相对上半部爆破施工及技术难度更大。以对土仓侧壁切割开口的方式提供爆破临空面,分层采用水压爆破步进,直至爆破完下半圈岩体。解决了全断面中风化花岗岩盾构卡壳问题,盾体成功脱困恢复掘进。

Due to the lack of examination of the cutter damage,the cut-diameter was too small and then the shiled was wrapped by the rock mass and could not continue the excavation during the construction of Guangzhou Metro Line 22.The conventional solution is to loosen the stratum from the blasting in the upper half of the excavation range,because the hard rock stable stratum at the top of the project is thinner,and the upper blasting is easy to cause the collapse of the upper stratum,so the lower blasting is chosen,which is more difficult than the upper in the blasting implementation.The blasting surface is provided by cutting an opening on the side wall of the soil wall of the silo,and the layering adopts water pressure blasting to step forward until the lower half of the rock mass is all blasted.The problem of weathered granite shield jamming in the whole section was solved,and the shield body was successfully broken out and resumed tunneling.