What is the critical depth of a vertical cut in a saturated cohesive soil with c = 1.5 t/m2 and γ = 1.8 t/m3
Critical depth = 2Zc
Passive earth pressure in a soil mass is proportional to
Passive earth pressure coefficient,
The earth pressure distribution due to surcharge load q per unit area is
The earth pressure distribution due to the surcharge load is = q.Ka and is uniform throughout the length of the retaining wall.
The factor of safety against overturning between the base of the wall and the underlying soil should be at least
Factor of safety against overturning is given by
and should be between 1.5 to 2
A retaining wall 8 m high with a smooth vertical back retains a clay backfill with c = 15 kN/m2, ϕ = 15° and γ = 8 kN/m3.
(Given sin 15° = 0.25). The pressure at the top will, nearly, be equal to
For c - ϕ soil active earth pressure,
at z = 0
A cantilever sheet pile derives its stability from
The active earth pressure on the back of the pile tries to push the wall away from fill and lateral passive resistance due to soil below the dredge line tries to restore the pile.
Consider the following assumptions:
1. Failure occurs on a plane surface.
2. Wall is smooth but not necessarily vertical.
3. Failure wedge is a rigid body.
Coulomb’s theory of earth pressure is based on assumptions
In Coulomb’s theory failure piane is assumed to be plane. The sliding wedge acts as a rigid body. The wall is assumed rough.
The following refer to the stability analysis of an earth dam under different conditions:
1. Stability of D/S slope during steady seepage.
2. Stability of D/S slope during sudden drawdown.
3. Stability of U/S and D/S slopes during construction.
Which of these statements are correct?
For earth dam during steady seepage, the critical condition occurs for D/S slope. For rapid drawdown case U/S slope represents critical condition. In both cases the pore water pressure is determined from flow net.
During construction, the excess pore pressure is likely to develop and stability of U/S and D/S slopes during or immediately after construction should be considered.
A saturated stiff clay has unit weight 2 gm/cm3 and unconfined compressive strength 2 kg/cm2. The depth of tension crack that would develop in this clay is
Depth of tension crack
Rankine's theory of earth pressure assumes that the back of the wall is
Rankine's earth pressure theory assumes that the retaining wall is smooth and vertical and the ground surface is piane which may be inclined or horizontal.