What is Boussinesq theory?
The Boussinesq theory for the distribution of stresses in a half-space resulting from surface loads is largely used in road engineering. It is based on the assumption of linear-elastic homogeneous isotropic half-space for the soil media.
How do you calculate vertical stress?
Total stress below a river or lake The total stress is the sum of the weight of the soil up to the surface and the weight of water above this: Vertical total stress at depth z, sv = g . z + gw .
How is influence factor calculated?
The influence factor is calculated in three points of reference: at the embedment depth of the foundation, at B/2 from the basement level ( I zp, max ) and at 2B from the basement of the foundation.
How do you calculate stress distribution?
Example: Determine vl stress σz at point A(r,z) = (2, 2 ) where Q = 100 KN/m. To calculate stresses distribution under triangular strip load must be known the distances C, Z, X. The distance X measured from zero load to direction of point (A).
What is r in Boussinesq equation?
Boussinesq’s Formula Equation where, r = the horizontal distance between an arbitrary point P below the surface and the vertical axis through the point load Q. z = the vertical depth of the point P from the surface.
What is 2 1 stress distribution method?
Approximate 2:1 Distribution An approximate stress distribution assumes that the total applied load on the surface of the soil is distributed over an area of the same shape as the loaded area on the surface, but with dimensions that increase by an amount equal to the depth below the surface, Fig-1.
How do you calculate horizontal stress and vertical stress?
In other words the vertical stress (σv) and horizontal stress (σH) are principal stresses. The horizontal stress is customarily expressed as a proportion of the vertical stress σH = K’o σv = K’o ρd gz (3.2) where K’o = coefficient of earth pressure at rest in terms of effective stresses (see equation (3.7)).
What is strain influence factor?
As is known, when the water table rises into the influence zone of footing, it reduces the soil stiffness and thus additional settlement is induced. The strain influence factor values are given for Poisson’s ratio value of soil, ranging from 0 to 0.5 with 0.1 interval.
What is the stress distribution?
From the perspective of what is happening within a material, stress is the internal distribution of forces within a body that balance and react to the loads applied to it. The stress distribution may or may not be uniform, depending on the nature of the loading condition.
Why is Boussinesq equation still used?
In geotechnical engineering practice, the Boussinesq’s equation is widely used for two reasons. It is simpler than the Westergaard’s equation and since the vertical stress estimates are greater from the Boussinesq’s equation, it can only overestimate the loadings within the soil, and hence be a conservative one.