Stability problems in rock engineering

220.019, 2015W, SE

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Tunnel 1 Alexander PREH & Alfred ZETTLER www.ig.tuwien.ac.at, alexander.preh@tuwien.ac.at

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Stability problems in rock engineering

220.019, 2015W, SE

Tunnel 1 Alexander PREH & Alfred ZETTLER www.ig.tuwien.ac.at, alexander.preh@tuwien.ac.at

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Stability problems in rock engineering

220.019, 2015W, SE

Tunnel 1 Alexander PREH & Alfred ZETTLER www.ig.tuwien.ac.at, alexander.preh@tuwien.ac.at

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Stability problems in rock engineering

220.019, 2015W, SE

Tunnel 1 Alexander PREH & Alfred ZETTLER www.ig.tuwien.ac.at, alexander.preh@tuwien.ac.at

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Stability problems in rock engineering

220.019, 2015W, SE

Tunnel 1 Alexander PREH & Alfred ZETTLER www.ig.tuwien.ac.at, alexander.preh@tuwien.ac.at

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Stability problems in rock engineering

220.019, 2015W, SE

Tunnel 1 Alexander PREH & Alfred ZETTLER www.ig.tuwien.ac.at, alexander.preh@tuwien.ac.at

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Stability problems in rock engineering

220.019, 2015W, SE

Tunnel 1 Alexander PREH & Alfred ZETTLER www.ig.tuwien.ac.at, alexander.preh@tuwien.ac.at

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Stability problems in rock engineering

220.019, 2015W, SE

Tunnel 1 Alexander PREH & Alfred ZETTLER www.ig.tuwien.ac.at, alexander.preh@tuwien.ac.at

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Stability problems in rock engineering

220.019, 2015W, SE

Problem statement: A circular tunnel (D=4m) is constructed in rock at the point with 185,20 m overburden and it is assumed that a circular support (e.g. shotcrete) is installed immediately after boring the tunnel. Also, it is presumed that tunnel is under a hydrostatic in-situ stresses. Parameters of rock and support are as below: Rock:

Φi=25◦

ci=0,03MPa

Er=1000 MPa

νr=0,25

K=1,03 (Labasse, 1949)

Φr=20◦

cr=0,03 Mpa

γ=27 kN/m3

Support:

Er=4000 MPa

νr=0,18

Questions: 1) Determine the thickness of the support required to limit the radial convergence (ur) to 35mm.

What is the support pressure on the lining? What is the tangential compressive stress in the lining? (it is assumed that the shotcrete properties are for a ‘young shotcrete’)

2) If before installing the shotcrete, 25mm of radial deformation is observed, determine the total

deformation and the support pressure when equilibrium is reached.

It’s recommended to use Excel, Matlab or Python to solve the problem!

Tunnel 1 Alexander PREH & Alfred ZETTLER www.ig.tuwien.ac.at, alexander.preh@tuwien.ac.at

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