1 (50 marks) (a) Explain, together with diagrams, what is meant by (i) compatibility, (ii) equilibrium and (iii) material properties with reference to bound solutions. Discuss how each above is satisfied or not by (I) upper bound solutions and (II) lower bound solutions. [15 marks] (b) Figure Q1 shows a 20m long foundation built at the crest of a 45o slope of 30m height. Using the proposed upper mechanism with two rigid blocks 1