Abstract: During the construction of Taiping tunnel of Xuanhe Expressway in Hubei Province, a large karstic cavern was encountered. The rock cavern had the characteristics of large size, a large number of broken rocks accumulated at the bottom and the high probability of falling rock hazards from top of rock cavern, which brought great difficulties to the tunnel excavation. Through the geological survey of karst rock cavern, this paper presents a design approach that spanning over the rock cavity to ensure the safety of workers during the construction and to reduce the operation cost in the service.

Key words: Tunnel Engineering, Large Karstic Rock Cavern, Remediation Measures