... concrete support reservoir geomechanics variation loading test Castelo extensometer borehole analytical solution tunnel Reservoir Characterization external pressure safety rock mass internal pressure verification underground structure contribution Bode tunnel carlson extensometer...

... of rocks surrounding the tunnel, underground water external pressure including the cases where water filtration through the lining is possible. The method is based upon a substitution of a rock deformation modulus continious change by a discrete change upon the solutions of corresponding elasticity theory...