山岭隧道围岩分级超前预报新方法研究

New Forecast Method of Surround Rock Classification of Mountain Tunnel

针对岩浆岩、变质岩等硬质岩地区的隧道,在无不良地质的情况下,由于结构面发育程度不同而导致围岩实际级别与设计级别不一致的区段,提出了以掌子面的结构面线密度快速判断掌子面围岩级别,然后根据地质雷达探测结果对掌子面前方一定距离的围岩级别进行定性与定量综合判断的方法.将上述方法应用于在建京台高速公路的岩前隧道和八外洋2#隧道的8个受结构面发育程度控制的围岩级别变更断面的结果表明,上述方法对由于结构面发育程度不同而导致的围岩级别变更预报有较高的可靠性,对后续的隧道施工具有较好的指导意义.

Aiming at igneous rock and metamorphic rock which is hard, when there is no disadvanta- geous geological phenomenon, because of the development of the structural surface level is different, so it may lead to the actual surround rock grade inconsistencies in the design grade in some sections. In these cases we can quickly determine the surrounding rock grade of heading face by the density of the structure surface. Then we can conjecture the grade of surrounding rock in front of the heading face according to the detection result of the geological radar and the information of the heading face. The application of the way in Yanqian and Bawaiyang 2# tunnel whose surrounding rock grade need to be changed because of the design is not agreed with the reality whose surrounding rock grade is con- trolled by structure surface, the ten application result indicate that the way is reliable in judging the surrounding rock grade of heading face and a certain distance ahead of it. It can provide important guidance for following construction.