引水隧洞下穿铁路隧道近接施工振动影响研究

结合云南省盐津县白水江三级电站引水隧洞下穿内-昆铁路手扒岩隧道的工程实际，采用数值模拟计算及现场测试对既有铁路隧道受下穿引水隧洞施工产生的振动影响进行研究。结果表明，经验公式的计算结果作为预测及警示是偏于安 全、可行的，数值模拟分析结果比经验公式更接近工程实际；引水隧洞的掌子面距铁路隧道前后4D（D为引水隧洞开挖洞径）范围内施工时，需对铁路隧道交叉点处的振动速度进行监测，重点是竖直方向的振动速度；引水隧洞在铁路隧道正下方爆破施工时，爆破施工所采用的最大段装药量不得大于2.5 kg，以满足振动速度控制标准；施工过程中进行的爆破振动监测并根据监测结果及时调整爆破参数，是此类地下近接工程成功修建的有力保障。

Study on vibration influence of nearby excavation of a traversing diversion tunnel on above existing railway tunnel

This paper gives an analysis of blasting vibration influence of a traversing diversion tunnel construction on the above existing railway tunnel, by using numerical methods and field test , associated with the practical situation of Shoupayan Tunnel of Nei-Kun Railway which was traversed by the diversion tunnel of Baishuijiang Cascade Ⅲ Hydropower Station in Yanjin Yunnan Province. The analysis result indicates that, empirical formula’s results are safe and feasible. Numerical simulation results are more contiguous with engineering practice than those of empirical formula. When the distance between diversion tunnel face and railway tunnel is less than 4D (D is the hydraulic tunnel diameter), the vibration speeds at the point of intersection in railway tunnel must be monitored, especially for the vertical vibration speed. When constructing the diversion tunnel under the railway tunnel, the detonator of the maximum segment should be less than 2.5kg in order to satisfy control criterion of vibration speed. The blasting vibration monitoring in the course of excavation and the blasting parameters modification timely according to monitoring results are the guarantees for the successfully nearby excavation.