Review of squeezing phenomenon in an under construction tunnel of Haraz road
| Category | Engineering Geology |
|---|---|
| Group | GSI.IR |
| Location | 3rd Iranian rock mechanics conference |
| Holding Date | 10 March 2008 |
Abstract:
After excavation of a tunnel in Alpain mountains, rock squeezing as an important phenomenon in rock mechanics has noteworthy. squeezing phenomenon is as a big convergence related to time dependent behaviour of a material surrounding in a tunnel after excavation. Magnitude of the convergence, rate of deformation and area of yelding zone are dependent to geological and geotechnical condition, in-situ steress condition, underground water, pore-pressur water and rock mass properties. A New tunnel is considered to be constructed in Tehran-Amol,(Haraz) road wich has 9 m height and 12 m width. In this tunnel it is possible to occur failure according to underground water condition, discuntiniu and faults, in sandstone and shales layers of different formation. In this reaserch by considering of geological and geomechanical properties of the rock layeres, the squeezing phenomenon is studyed by empirical and semi-empirical and analytical methods. Results shown that value of squeezing is very high in the shale layer of Shemshak formation and failure occured. Also, in marl with enterlayer of limestone and limestone with Big thickness are shown squeezing phenomenon, but smaller than the shale layer, in the length of the tunnel.
Key words: Squeezing, Shale, Sandstone, tunnel convergence, uniaxial compersive strength, tunnel of Hraz road
After excavation of a tunnel in Alpain mountains, rock squeezing as an important phenomenon in rock mechanics has noteworthy. squeezing phenomenon is as a big convergence related to time dependent behaviour of a material surrounding in a tunnel after excavation. Magnitude of the convergence, rate of deformation and area of yelding zone are dependent to geological and geotechnical condition, in-situ steress condition, underground water, pore-pressur water and rock mass properties. A New tunnel is considered to be constructed in Tehran-Amol,(Haraz) road wich has 9 m height and 12 m width. In this tunnel it is possible to occur failure according to underground water condition, discuntiniu and faults, in sandstone and shales layers of different formation. In this reaserch by considering of geological and geomechanical properties of the rock layeres, the squeezing phenomenon is studyed by empirical and semi-empirical and analytical methods. Results shown that value of squeezing is very high in the shale layer of Shemshak formation and failure occured. Also, in marl with enterlayer of limestone and limestone with Big thickness are shown squeezing phenomenon, but smaller than the shale layer, in the length of the tunnel.
Key words: Squeezing, Shale, Sandstone, tunnel convergence, uniaxial compersive strength, tunnel of Hraz road