TGP在大坪山隧道地质预报中的应用效果分析

Analysis on the Application Effectiveness of TGP System to the Advanced Geological Prediction for Dapingshan Tunnel

大坪山隧道是谷竹高速公路的一座特长隧道,穿越区域性的青峰断裂带,且地质构造复杂、断层破碎带多,进行超前地质预报是隧道安全施工的重要保障。本文介绍了TGP超前地质预报系统的基本原理和主要技术优势,并通过实例分析了TGP在大坪山隧道不同地层中的预测效果。结果表明:软岩中尤其是在没有大规模不良地质体的岩层中,TGP的探测结果与实际情况稍有出入;但在断层破碎带等与围岩介质波阻抗差别较大的不良地质体的岩层中,TGP的预测结果比较准确。同时,指出TGP作为一种物探手段,应在地质调查分析的基础上,结合其他技术手段,以提高地质预报的效果。

Dapingshan Tunnel is a big and long tunnel of GuchengZhuxi Highway in Hubei Province; it goes across Qingfeng fault,where the geological structure is complex and the rock is fragmented. For the purpose of ensuring the construction safety and decreasing geological hazards in the construction process, the advanced prediction approaches based on TGP are applied. First of all, this paper introduces the basic principles of TGP system,and then it analyzes the flexibility issues in the application of TGP system to dif ferent lithology strata by the basic principles and practical examples. The results show that the forecast re sult of TGP is not very accurate in soft rock,especially that without the large adverse geological body;the forecast result is more accurate in the large adverse geological body,whose difference of medium wave im pedance is large, such as fault fracture zone. For TGP, as a geophysical means,its application should be on the basis of the analysis of geological survey and in conjunction with other technical means so as to improve the geological prediction effect.