(i). Calculate lateral earth pressure for the basement structure. Use the following data, depth of wall 8m, cohesion = 0, angle of friction = 25°, soil type = clay, OCR=2.0, bulk unit weight = 19 kN/m3. (ii)What will change if we would have coarse sand behind the retaining wall instead of clay? Assume compacted coarse sand behind retaining wall and get the recommended values of Cohesion and friction for sand from literature and calculate lateral earth pressure for wall with dimensions given in section (i) and compare both results.