A temporary earth retaining wall consists of planks driven vertically into the ground. The wall is designed to resist $2\mathrm{.}4m.$ height of soil.

Given:

Plank dimension: $300mm$ wide $75mm$ thick

Plank allowable stresses:

Bending $=10\mathrm{.}4$MPa

Shear $=0\mathrm{.}8$MPa

Unit Weight of Soil $=17\mathrm{.}3k\frac{N}{m}3$

Active earth pressure coefficient $Ka=\frac{1}{3}$

Which of the following gives the maximum flexural stress?

A temporary earth retaining wall consists of planks driven vertically into the ground. The wall is designed to resist $2\mathrm{.}4m.$ height of soil.

Given:

Plank dimension: $300mm$ wide $75mm$ thick

Plank allowable stresses:

Bending $=10\mathrm{.}4$MPa

Shear $=0\mathrm{.}8$MPa

Unit Weight of Soil $=17\mathrm{.}3k\frac{N}{m}3$

Active earth pressure coefficient $Ka=\frac{1}{3}$

$1.)$ Which of the following gives the maximum flexural stress?

$2.)$ Find the maximum shear stress?

$3.)$ What should be the fhickness of the planks to avid failure?