Use the NAME_1 Equations and an Excel spreadsheet to predict stresses around a circular tunnel with 4 m radius. Assume the rock mass is elastic with the following parameters: E = 10 GPa, µ = 0.25, specific gravity = 2.3.  The insitu stress can be estimated assuming a depth of 500 m below the ground surface and K = 2.5 (K = horizontal/vertical insitu stress).

What is the magnitude of the tangential or hoop stress at the roof? [MPa] Do not include the following keywords: magnitude, spreadsheet, horizontal, gpa
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