The way you have written about your assignment, it can be done in different ways. One way has been mentioned by Umar, which involves calculation of strength of beam.
There could be another way, the easier one. Perform linear elastic F.E analysis on your deep beam, and then compare the results- which could be deflection, bending strains and shear strains- with Themoshenko equations that take into account bending , as well as, shear deformations. You can find these equations in "Timoshenko S.P. and Gere J.M., (1971), Mechanics of materials, Van Nostrand Reinhold Company", or "Timoshenko S.P., (1957), Strength of Materials – Part I, D. Van Nostrand Co. Inc., London, England".