国内外隧道超前预报技术评析与推介

Analysis and recommendation of tunnel prediction techniques at home and abroad

国内外的隧道地质超前预报技术正在发展之中,目前应用的负视速度法,水平剖面法,TSP、TGP等技术,由于观测方式和资料处理方法比较简单,不能准确确定掌子面前方围岩的波速,从而致使地质界面定位不准确,围岩工程类别划分缺乏依据,亟待改进.TRT与TST技术采用空间观测方式和偏移成像方法,技术比较先进,能解决了掌子面前方围岩速度结构可靠分析的问题,实现了隧道围岩地质结构的精确成像,适合复杂地质条件下的地质超前预报应用.目前的超前预报过于依赖地震方法,实际上地震方法对于解决构造问题比较有效,解决含水性问题不如电磁方法,高密度电法和瞬变电磁方法在超前预报领域会有广阔的应用前景.实际预报工作中要取得好的预报结果,必须提倡综合方法,提倡地质分析与工程物探相结合,地震方法与地磁方法相结合,共同解决不良地质构造、含水构造、含瓦斯气构造的超前预报问题.

Current typical techniques of tunnel geological prediction at home and abroad is under developing, including negative apparent velocity, horizontal section profile（HSP） and TSP method etc. Considering simpler observation way and data process, it is hard to accurately determine the seismic wave velocity of wall rock in the front of tunnel face. Therefore, from these defective methods, geological interface may he inaccurate, which will not provide sufficient evidences for classifying wall rock Characteristics. The TRT and TST methods with spatial observation arrange and data process of migration image can solve the problems of analyzing velocity structure of wall rock in the front of tunnel face and realize accurate image of geological framework of tunnel wall rock. At present, tunnel prediction technology study pays more attention on seismic techniques. However, seismic technique can solve geological structure problems, hut it is not powerfully to solve water bearing problem as electromagnetic techniques. Such Electric Resistivity and TEM methods maybe have wide application in the future. To oh tain good results in prediction practices, it is necessary to recommend synthetical methods, such as combining of geological analysis and geophysical examination, of seismic and electromagnetic methods, to meet the prediction of geological structure, water and gas bearing problems.