Question

1. A retaining wall of height 7 m retains soil having an unsurcharged horizontal surface. The soil properties are c' = 0, Ⓡ' = 32, y = 18 kN/m3 and Ysat= 20 kN/m3. i. ii. Determine the distribution of horizontal stresses on the wall and the magnitude of resultant thrust when water table is at 3 m below the ground surface Determine the magnitude of resultant thrust when the water table is well below the base of the wall Determine the magnitude of resultant thrust when the water table is at the ground surface (no seepage flow) Determine the location of resultant thrust for all cases above iii. iv.

Answer 1

> Horizontal stress distribution. magnitude of resultant thout = Area of all pressure diagram Solution :- Dota given, C=0,0-32°, Y = 180mmlyset - Everym3 (" when water table is 3m below ground surface Hi=3m Y=184N/m? 0-39° kayn 16.578 Ysat = 80 kr/m3 42=1ml $2328 @ © Kaylny الإحالا kayni 12.51 1439.244 a where ka 1-sin32 It sim 32 = 0.307 Y' - = Ysar-Yw = 20-9.81 - 10.19 un/m3 & Yw = 9.81 kn/m3 + FR = Ai+Az + A3 + AG **16-578x3+ 16-578*4 + $*12.51X4+*39.24x4 = 24.867 +66.312 + 25-02 + 78.48 = FR = 194.68 km/per meter length of refaining wall

("" when water table is well below the base of the wall. does mot influences the hunizem tal Strom 2:e water table ham Y = 186N/m3 0=32° Ka=0.307 ka УН 38.68 FR = x kayh xй = 2 x 38-68x7 135:38 ww/on FR = 135.38 un per metre length of wall (1) When water table is at the ground surface Ysat=204/on3 N=7m Ysubmerged =10.196/m3 a 0 - 320 ka=0.307 Iywn key'll 21.898 68.67 Resultant force - AirAZ 11 ** 21.89887 + 68.6787 = 76.643 + 240.345 = 316.9886/m fR = 316.988 kN/ Per meter length of wall-

for location of resultent thrust In case ci forom boton (base of wall Aigi + Azgz +Azgz + Aq ya - - Alt Azt A3 +Aq 2 =) ģ 24.867* (4+}) + 66'312 x 2 + 25.02+ 78.48X2 194.68 Cal = 9.0287 am location of resultant thount for case (3) from base. In case II = 8.33m . » 1/2 = 27 / + g = 2.33m from base of the wall & & Ja case l in ğ = Aigi + Az Yz = Art Az 2) ỹ 76.643x / + 240 345X272 316.988 7 ý = 2/2 = 2.33m from the base of the wall.