Civil Engineering - Soil Mechanics and Foundation Engineering - Discussion

Option B is right

Lateral earth pressure= k.w.h
(So directly proportional to h)

Lateral earth pressure force* = 0.5 k.w.h^2.

(It's force directly to h^2 but not pressure)

Here K depends on the angle of internal friction(θ) and retaining wall condition (active/at rest/passive).

For example At rest K = 1-sin θ.
Here lateral earth pressure and K decrease as the angle of internal friction θ increases. So lateral earth pressure is not directly proportional to the angle of internal friction.

I think the answer given here is right,

See the problem here, asks about lateral pressure that is major stress and not active or passive earth pressure intensities. As per Bell's Formula on stresses,

P1 = P3* tan^2(α) + 2C*tan(α)

Hence here P1 i.e. Lateral Stress is directly proportional to the angle of internal friction.

Lateral earth pressure is horizontal earth pressure.

We know k is lateral pressure/vertical pressure;
K= 1- sin(fi) /1+sin(fi)
Where fi is angle of internal friction.
Kwh is pressure intensity.
And o.5kwh2 is total pressure per metre length.
Hence lateral pressure proportional to the angle of internal friction.

In the question they asked lateral earth pressure not total pressure so, pressure p=co-efficient (k) *vertical stress (unit weight of soil (&gama;) * depth of soil).

From this equation, Pressure P is proportional to both K and depth of soil. Hence option B and D are correct.

Only "c " is the correct answer. Because pressure is directly proportional to the square of depth "B" is not a correct answer. And in the case of option "D" according to the active earth pressure coefficient "K " is inversely proportional to the internal angle of friction.

It's correct.

Lateral earth pressure means horizontal earth pressure, which is proportional to phi in rest, active and also in the passive state both in Rankine's and Columb's theory.

@Rest=1-sin π.
@active=1-sinπ/1+sinπ,

And @passive = 1+sin&π/1-sinπ.

The Lateral earth pressure is directly proportional to the depth of soil because p=kwh.
The lateral earth pressure force is directly proportional to the square of the depth of soil
P(pressure force)= area of pressure diagram = 0.5kwh^2.

I think B and D are right because p = k*w*h, so p is proportional to depth and co-efficient of lateral earth pressure in this k = 1-sin (pi).

So k depends on internal friction then pis also directly proportional to internal friction.

@Harpreet Singh,

P = 0.5 kwh^2, in this formula P, is lateral pressure force per running meter length of the wall, lateral pressure is proportional to depth and angle of internal friction as well.

There are two things one is pressure intensity and the other is total pressure. Intensity is proportional to the depth of soil and the total pressure is proportional to the square depth of soil.