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Uplift on a Raft: Groundwater table fluctuates; However, site investigation companies can monitor GWL (piezometers are used for this purpose) over time and get a fair assessment of the water table. If you are founding on impermeable clay, then you can get a perched ground water table and pressure. In some countries with a lot of rain they assume GWL at 1m below ground level .... unlikely in majority of Pakistan where ground water levels/table are sinking (a major worry for future PK generations that we are not now addressing in our ignorance). Uplift Calc: Working to metric units: 2' above GWL = 0.6m; Uplift = 10x0.6= 6kN/sqm (can be resisted by 0.25m (equivalent to 10" thickness of concrete!) - hence uplift should not an issue! RAFT and building DEAD WEIGHT would be much greater! Say FoS= 1.1 against uplift and take Dead weight load factor as 0.9, for conservative design check. As @Ayesha said check fluctuation of Ground Water Table with the geotechnical engineer - geotechnical Engineers and their investigation report worth needs to be appreciated! There may be other practical construction related issues with constructing a raft under water - hence ground water level would need to be temporarily lowered - should not be an issue of the experienced builder who knows what he is doing.

Water table can seasonally fluctuate and you can have a condition where the soil below raft is submerged in water. In that case, bearing capacity of the soil would be reduced to some degree. Speak with your geotechnical consultant to get the exact number. You can do a separate buoyancy check if you want but I don't suggest providing an uplift pressure and you might not end with a lower bound solution.