A timber pile having a cross sectional area A=64,000 mm? was driven into the soil to a depth L=10 m. The soil's friction force per unit length, f (in kN/m), varies parabolically from zero at the bottom of the pile to a maximum value at the ground level such that f=ky (where k=0.75 kN/m' and y is measured from the bottom of the pile in meters). The bearing stress capacity of the soil at the bottom of the pile is given as a function of the depth L (in meters) as Obearing=0.3125XL (bearing in MPa, Lin meters) What is the maximum force F that the pile can carry?

Find the axial stress in the pile as a function of y.

Determine the total shortening of the pile if its modulus of elasticity is E=10 GPa. 2 . P. bearing .