When the water table is close to the soil and clay, what is the best way or the style of the founding of the 5-storey building?

There are following methods;

Install02 Peter Engine Pumps & execute dewatering, then provide hard core/stone soling and then execute raft foundation.

The other way is to execute Piles by Reverse Rotary Method of Drilling

In some cases it might be necessary to combine the two methods and make a raft foundations based on micropiles.

The calculation will be based on the total weight of building and the combined bearing capacity of the raft and the micropiles; raft will rely on compression strength and micropiles on shear strenght.

the best is to use a combined footing, after checking for the bearing capacity of the soil, employ a combination of raft, and pad foundation/small piles.the raft will take care of the water pressure and the pad or small piles will take care of the servicability design load. but ensure water is properly drained from the area to to stabilze the ground before contruction

Piles:

For expansive soils or soils that are compressive with heavy loads where deep soils can not take the building load and where soil of better capacity if found deep below

i think it is more economic and safe to use replacement of gravel with 2 meter depth and on it use plain concrete and use isolated footing

Engage the use of raft foundation