what is the relation between car park basement and SOIL MECHANICS??

Answer 1

car mechanics work above the basement floor. soil mechanics works below the basement floor.

"soil mechanics" is the engineering study done to determine how the ground is capabable of supporting a load, such as the load of a building structure on top of it. If the car park basement when parked full of cars presents too much of a load bearing on the ground, there will be a support failure. most likely a wall will buckle and that could bring down the house.