摘要
掌子面前方富水构造是隧洞安全施工的重大隐患,盲目掘进易造成岩体大面积涌渗水,威胁生命财产安全,影响施工进度.将地质雷达与TSP303用于千岛湖配水工程隧洞含水构造超前探测,简述了隧洞地震反射波法探测原理及隧道地震波预报(TSP)观测系统布设方式,模拟了电磁波在含水构造中的传播特性,分析了影响TSP数据采集及处理质量的关键因素,统计了千岛湖引水线路不同质量级别下常见岩性的TSP物理力学指标分布区间,综合物探成果准确反映了掌子面前方不良地质的性质及规模,为后续隧洞施工提供了重要指导.结论如下:炮孔角度向下倾斜以改善炸药的水封效果是提高TSP数据信噪比的关键,反射波拾取过程中最大增益与Q值对TSP预报结果影响大,建议两者在15～25区间取值;相同质量级别下安山岩对应TSP物理力学指标最高,灰岩次之,但较凝灰岩、熔结凝灰岩略高,砂泥质岩最差;含水破碎带与充水方解石结晶洞均对应强振幅、低主频(多大于50 MHz)的电磁异常特性,但前者同相轴错断,后者呈双曲线状,含水构造在TSP成果中表现为视波速、密度及各力学模量值偏低,泊松比偏高.
The water-bearing structure which locates in front of the tunnel face is a significant safety hazard in tunnel safety construction,blind rock excavation may be causing water gushing in large area of rock mass which threatens the life and property safety and affect the construction schedule.We use ground penetrating radar and TSP303 to the detection of water-bearing structures in tunnels of Thousand Island Lake-Hangzhou water transfer project.Then we give a brief description of the detection principle of seismic reflection wave method and the observation system of TSP(Tunnel Seismic Prediction).Thirdly,we simulate the propagation characteristics of electromagnetic wave in water-bearing structures and analyze the key factors which influencing the prediction accuracy of TSP.Lastly,we calculate the range value of physical and mechanical indexes of TSP in different classification of rock mass basic quality in the routes of Thousand Island Lake water transfer project.Comprehensive geophysical results accurately reflect the property and scale of unfavorable geology in front of tunnel face which provide an important guidance for the subsequent tunnel construction.Several conclusions are drawn as follow.Firstly,the shot hole which designs slanting downward for improving the water seal effect of explosive is the key to improve the signal to noise ratio of TSP data.Secondly,the maximum gain and Q value in the reflection wave pickup process have great influence on the results of the TSP prediction,both of them are suggested taking the value in the 15~25 interval.Thirdly,in the same quality level,andesite corresponds to the highest physical and mechanical index of TSP,and the limestone is second,but it is slightly higher than that of tuff and melted tuff,the sandstone and mudstone is worst.Fourthly,water-bearing fracture zone and water-filled calcite crystalline cavity both correspond to the electromagnetic anomaly characteristics of strong amplitude and low main frequency(more than 50 MHz),the event for the former is broken
作者
李俊杰
张红纲
何建设
朱红雷
郭佳豪
LI Jun-jie;ZHANG Hong-gang;HE Jian-she;ZHU Hong-lei;GUO Jia-hao(Zhejiang Design Institute of Water Conservancy and Hydroelectric Power,Hangzhou 310002,China)
出处
《地球物理学进展》
CSCD
北大核心
2019年第2期737-744,共8页
Progress in Geophysics
基金
国家自然科学基金项目(41641040)
浙江省水利厅科技项目(RC1729)联合资助
关键词
隧道地震波预报(TSP)
地质雷达
千岛湖配水工程
含水构造
超前探测
Tunnel Seismic Prediction(TSP)
Ground penetrating radar
Thousand Island Lake water transfer project
Water-bearing structures
Advanced detection
