ABSTRACT
This paper presented a case study of super large Karst cave in highway tunnel construction, based on the generalized analysis of engineering geology and hydrogeology in the Taiping Tunnel project of Xuan’en- Hefeng Highway in Hubei Province, a variety of technical schemes for crossing the karst tunnel are compared and selected, so comprehensive approach with double-arch open-cut tunnel combing backfilling and underground excavation was proposed. This technique can reduce the backfilling volume and meet the requirements of safety and economy. Meanwhile, monitoring measurements are carried out for the project, and the results show that the tunnel settlement had experienced two deformation stages, the deformation in the rapid settlement period can account for more than 82.6% of the total deformation, and the deformation in convergent settlement period accounts for less than 20% of the total deformation. This technology can significantly improve construction efficiency and safety and effectively prevent major risks.
