Apr 14, 20202 min

Soil Mechanics (121-140)

Updated: Apr 27, 2020

121. Sensitivity of a soil can be defined as ratio of compressive strength of

unconfined undisturbed soil to that of soil in a remoulded state


122. Rankine's theory of earth pressure assumes that the back of the wall is

vertical and smooth


123. The coefficient of active earth pressure for a loose sand having an angle of internal friction of 30° is 1/3


124. The major principal stress in an element of cohesionless soil within the backfill of a vertical if the soil is in an active state of plastic equilibrium


125. Passive earth pressure in a soil mass is proportional to

where μ is Poisson's ratio and Φ is the effective angle of internal friction of soil


126. The effect of cohesion on a soil is to reduce the active earth pressure in

tensity but to increase the passive earth pressure intensity


127. A retaining wall 6m high supports a backfill with a surcharge angle of 10°. The

back of the wall is inclined to the vertical at a positive batter angle of 5°. If the angle of wall friction is 7°, then the resultant active earth pressure will act at a distance of 2 m above the base and inclined to the horizontal at an angle of

12°


128. Coefficient of earth pressure at rest is greater than active earth pressure but

less than passive earth pressure


129. If the top surface of the backfill of a retaining wall is inclined to the horizontal

at an angle β, then the coefficient of passive earth pressure is equal to


130. The critical height of an unsupported vertical cut in a cohesive soil is given by


131. Total lateral earth pressure is proportional to square of depth of soil


132.Cohesive soils are poor for backfill because of large lateral pressure


133.Which of the following earth pressure theories is directly applicable to bulk

heads?


134. Taylor's stability number is equal to


135. For a base failure, the depth factor Df is D f> 1


136.Base failure of a finite slope occurs when the soil below the toe is relatively soft and weak


137.Bishop's method of stability analysis assumes the slip surface as an arc of a

circle


138.Allowable bearing pressure for a foundation depends upon both allowable settlement and ultimate bearing capacity


139.According to Rankine's analysis, minimum depth of foundation is equal to

where q = intensity of loading

γ = unit weight of soil

Φ = angle of internal friction


140.According to Terzaghi's theory, the. ultimate bearing capacity at ground surface for a purely cohesive soil and for a smooth base of a strip footing is

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