高地应力区大直径TBM掘进岩爆风险控制

ROCKBURST RISK CONTROL FOR LARGE DIAMETER TBM BORING IN HIGH GEOSTRESS REGION

锦屏二级水电站1#,3#引水隧洞采用TBM掘进,中部深埋洞段岩爆风险突出。为制定合理可行的掘进方案与岩爆防治措施,在前人研究基础上,结合工程实际情况,采用多种数值分析手段,评价不同形式导洞开掘,对降低岩爆风险的影响。3种导洞开挖方式均可以显著地降低TBM掘进的岩爆风险,选择何种形式的导洞主要从设备和经济效益角度进行决策。据此提出高地应力区大直径TBM掘进岩爆风险控制措施,施工中结合钻爆法导洞预处理、应力解除爆破并辅以及时、系统、高质量的支护,降低岩爆风险,确保施工及结构安全。

Water diversion tunnels #1 and #3 of Jinping II hydropower station are bored by tunnel boring machine（TBM）. The rockburst risk is high in the middle alignment. For the purpose of establishing reasonable boring scheme and rockburst control measurement,based on previous researches,different numerical methods are used to evaluate different pilot boring schemes′ effects on reducing the rockburst risk,combining with actual situation. All these three pilot boring schemes can obviously reduce the rockburst risk. The selection of pilot boring schemes depends on the equipment and economic benefit factors. So,rockburst risk control measurements for large diameter TBM boring in high stress region are proposed. During TBM boring,the measurements of pilot,stress relieving blasting,assisting timely,systemic and high quality support are applied to reduce rockburst risk and ensure construction and structure safety.