1) Lateral resistance to counteract the horizontal thrust Try a thrust block of size L 3.2 m W 3.2 m H 3.2 m Weigh of thrust block = 75.3664 Ton Weight of water in the pipe = 2.03472 Ton Weight of earth = 5.184 Ton Total weight = 82.58512 Ton Total force available considering frictional resistance of soil 24.77554 Ton 2) Lateral resistance of soil against the block
Sin Φ = By assuming cohession C as 0 fp Total lateral resistance = Total horizontal thrust = Factor of safety =
0.5 88.4736 Ton 113.249 Ton/m2 53.55959 Ton/m2 2.11445 OK
Reinforcement
The minimum surface reinforcement in all thrust blocks shall be 5 Kg/sqm (as per IRG 21-1972 Arti The spacing of these bars is not to exceed 500mm. Hence provide 10 tor bars at 200 c/c which is m
Coefficient of friction
per IRG 21-1972 Article 306.4) s at 200 c/c which is more than 5 Kg/sqm