Ontario Power Generation's Response to the Joint Review

Table of Contents
CLOSURE WALL CAPACITY
1.0 INTRODUCTION ............................................................................................................................................................... 1
2.0 ASSUMPTIONS AND METHODOLOGY .......................................................................................................................... 1
3.0 ANALYSES ....................................................................................................................................................................... 1
3.1 Geometry of the Closure wall............................................................................................................................... 1
3.2 Shear Strength of the Interface ............................................................................................................................ 2
3.3 Shearing through Asperities (no dilation) ............................................................................................................. 2
3.3.1 Shear Strength of Rock .................................................................................................................................. 2
3.3.2 Shear Strength of Concrete ........................................................................................................................... 3
3.4 Frictional Interface (dilation leading to normal stress) .......................................................................................... 3
3.5 Closure wall Capacity .......................................................................................................................................... 4
3.6 Numerical Analyses ............................................................................................................................................. 5
4.0 CLOSURE WALLS IN RETURN AIR TUNNELS ............................................................................................................. 7
5.0 RECOMMENDATIONS ..................................................................................................................................................... 8
6.0 REFERENCES .................................................................................................................................................................. 8
FIGURES
Figure 1: Access tunnel geometry. ............................................................................................................................................. 2
Figure 2: Tunnel and closure wall geometry – boundary element mesh and load conditions. ................................................... 5
Figure 3: Shear stress distribution on the floor and side wall interfaces. .................................................................................... 6
Figure 4: Roof and side wall displacements due to 10 MPa pressure in the tunnel. .................................................................. 7
Figure 5: Return air tunnel geometry. ......................................................................................................................................... 8
August 27, 2012
Report No. 1011170042-TM-G2170-0001-00 i