SS
Yes you are correct the Burj tower in Dubai is built on sand with the help of the below !!!
"Over 45,000 m3 (58,900 cu yd) of concrete, weighing more than 110,000 tonnes were used to construct the concrete and steel foundation, which features 192 piles buried more than 50 m (164 ft) deep.
Stabilising the mud of the thames estuary will be like plaiting fog !
Having spent many an hour wandering the shoreline of the thames at low tide I can assure you that this stuff won't hold anything heavier than a seagull !!