Problem $3$: $(30$ Points$)$

Building shown in figure below weights $Q=30000kN$ and is supported by mat foundation. Base dimensions of the building is $20m10m$

Determine the total and effective stress values at $A,B,C$ and $D$ levels before the construction of the building

After the construction, determine the increase in vertical stress below the center of the foundation for $A,B,C$ and D levels by using the following methods:

Simplified assumption $(1/2$ stress distribution$)$

Assumption of rectangularly loaded area

What will be the vertical stress increase $5$ m below the ground surface at the corner of the foundation if the foundation is located $2$ m below the ground surface.