不同地质条件下盾构工程孤石处理工艺及实例

花岗岩风化土中存在的球状风化核,俗称"孤石",其埋藏分布及大小是随机的,且形状各异,直径从几十厘米到几米,岩石单轴抗压强度可以达到200 MPa以上。为解决盾构在存在孤石的花岗岩残积层中掘进时面临的极大施工风险,通过分析珠三角地区及台山盾构隧道工程的孤石处理工艺方法,总结各项目孤石处理的成功经验和失败教训,得出不同地质条件和不同工况条件下有效的孤石处理技术,这些处理技术包括:地下深孔爆破,冷冻、地面冲孔和人工挖孔,地表注浆以及盾构直接切削。

Treatment of Boulders Encountered in Shield Tunneling under Different Geological Conditions

Boulder is a kind of weathered granite core. The diameter of boulders ranges from dozens of centimeters to several meters and the uniaxial compressive strength of boulders can reach 200 MPa. The treatment technologies for boulders encountered in shield tunneling in Peal River Delta and in Taishan are analyzed, and the experience in boulder treatment is summarized, so as to minimize the risk of shield tunneling in ground containing boulders. The paper can provide reference for similar projects in the future. The treatment technologies inchuding underground deep hole blasting freezing, hole punching and hole cutting, groundsurface grouting and cutting by shield machines.