Question

please answer 2 and 3

i would really appreciate it :)

2. The 4 m tall concrete retaining shown in Figure 2 has the following properties: Backfill (Coarse sand): Ym = moist unit weight = 19.2 kN/m d' = effective friction angle = 40° The groundwater table will remain far below the wall, and the wall friction angle is 20°. Assume the backfill is not sloped and the wall has no batter. The wall moves sufficiently to develop the active condition in the soil. Using Coulomb's method, determine the overall resultant lateral force and its location. Sandy backfill with unit weight y and angle of internal friction o Figure 2: Retaining wall for Problem 2. Grad Students: Complete the above problems as well as the problem below. 3. Solve Problem 2 again, this time when the backfill has an angle (a) of 10° and the wall has a batter (0) of 20 Comment on the difference to your answers to this problem and problem 2. What effect did these changes have and why?

Answer 1

wre = w A. 0.199. Pa sol? Active earth Pressure = y karta where Ka= cost (0-0) Costacos (8+ Sin (8+) Sin (ora con (80) cos(0-2) is has cosłyo Cos (20)( 1+ / Sinyo sin(4 6420) J I cos(20) 3 285 0.199 30.56 X8 225x19.2x4² = 3 yefokN/m 1 Location at distance H/g from ban ije 4/3 = 1.333 (3) Ka= cos(40-20) Cosio cos(40)[1+ sin(60) sin(30172 cos(40) lascio ] $ 0.422 Pa = 1/2*0.422 x 19.2 x 42 = 64.91(Nim Location. H/3=1.33 from base The active force has increased because of increase in the active earth Pressure coefficient Due to the inclined backfill and bettering oh wan The vertical strenes decreased which resulted it increase of Ka since Ka= AGH деу ent