Study on the Impact of Hidden Karst Caves on Tunnel Excavation Stability
That study of the impact of hidden karst caves on the stability of tunnel excavation is very important for enhancing the safety and feasibility of tunnel engineering projects.Taking the Jinyan Tunnel of the Huhhot-Beihai Expressway as an example,a 3D finite element model of the tunnel was established by Midas GTS NX software to study the development of the plastic zone in the surrounding rock of the tunnel and the deformation and stress pat-terns of the tunnel lining under different locations,sizes,and distances between the karst cave and tunnel.The re-sults show that karst caves located laterally to the tunnel have the most significant impact on tunnel stability with the largest distribution of plastic zones in the surrounding rock.Followed by karst caves located at the bottom of the tun-nel,and finally,those at the top of the tunnel;The shorter the distance between the karst cave and tunnel,the greater the impact on tunnel stability.When the distance is sufficiently short,the development of the plastic zone will through the middle rock column between the tunnel and the karst cave;The surface V-shaped influence zone increases with the diameter increase of the karst cave as well as the distance between the karst cave and tunnel;The failure of the middle rock column is caused by the simultaneous plastic development towards the center from the sur-rounding rock on the side of the tunnel and the rock body on the side of the karst cave.The study can provide refer-ence for the safe construction of mountain tunnels in karst developing areas.
tunnelhidden karst cavestabilityplastic zone developmentkarst cave locationkarst cave sizedistance between karst cave and tunnel
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