system againt floating pipe

[carmoch]

Hello,

we have to install 2 pipes (100 inches each other) in a swamp area (soft clays with water level 1.5 m below ground). The trouble is that the client wants to install a layer of gravel or crush rock above the pipes for avoid the buoyancy. I don´t believe in that system because it could produce an important settlement in the foundation of the pipes. What´s your opinion? Could be possible a system with screw anchors? The thickness of soft soils is 10 meters.

Thanks!!!