Application of TSP and 3D Transient Electromagnetic Results in Prediction of Fault Water Content in Tunnel
In the process of tunnel excavation,geological abnormal sections such as fault zones and densely developed joint zones are often encountered,and the fault zones are prone to forming migration channels for groundwater.Identifying such geological issues in advance can minimize the safety risks during construction.The advance geological forecast for tunnels is a continuation of the preliminary investigation.During construction,geological conditions ahead of tunnel excavations can be effectively interpreted by geophysical prospecting,drilling and other means.For the first time,we combined the TSP method with the 3D transient electromagnetic results and applied it to the advance forecast for a railway tunnel under construction.The fault development sections were determined according to the preliminary investigation data and TSP detection results,and then the multi-angle transient electromagnetic detection was carried out near the tunnel face;the 3D display of the transient electromagnetic results was realized based on Voxler software,the water content of faults was judged based on the 3D results,the 3D distribution characteristics of transient electromagnetic low resistance anomalies and TSP wave velocity anomaly sections were comprehensively analyzed,the fault fracture range and the spatial distribution of water abundance were delineated,and drilling and drainage activities were carried out in advance for water-rich areas.The results of verification and analysis of actual excavation show that the combination of the two methods enables the accurate detection of the integrity and water content of surrounding rocks ahead of tunnel excavations,effectively reduces construction risks,and provides effective data for optimizing tunnel excavation schemes.
NETL
NSTL
万方数据
