Application of Transient Electromagnetic Method and Seismic Reflection Wave Method in Advance Geological Prediction of Hole Section with Poor Geological Conditions
Geophysical methods as the main means of advanced geological forecasting can de-tect and predict changes in geological conditions by using the differences in physical parame-ters between unfavorable geological bodies and surrounding rocks.When the physical param-eters of the intact or nearly intact rock bodies and the unfavorable geological bodies are sig-nificantly different,it is easier to identify the unfavorable ones.However,when the geolog-ical conditions are poor,the differences in physical parameters between the unfavorable geo-logical bodies and the intact or nearly intact rock bodies are very small,making it difficult to identify the unfavorable geological bodies,it is extremely difficult to predict the rock mass quality and geological disaster risks.This study integrates the geophysical method of transi-ent electromagnetic method and seismic reflection wave method in the special advanced geo-logical forecasting work for class V special rock mass in the Ⅱ section of the Dali section of the Yunnan-Guizhou water diversion project.The method mainly uses the parameters of rock body resistivity,stress gradient,longitudinal wave velocity,and transverse wave velocity to predict the rock mass quality and possible geological disaster risks in the unexcavated sec-tions.This study integrates the"daily progress"indicator in the creative evaluation of rock fragmentation in the excavated sections,the forecast results are 85.1％consistent with the excavation results,which have obvious reflection on the collapse and instability sections,and the sudden inrush of water and mud sections,providing reference for the application of the methods integration in the advanced geological forecasting of unfavorable geological sections.
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