I have actually no experience about pipeline but I've read something about "thermal ratchet". I don't know if this is the cause of the 2 meters movement. If your loop is buried underground(I don't know if I interpreted your question correctly), maybe the 100 mm movement was accumulated up to 2 meters through repeated "cool down" and "heat up" of pipe. "Thermal ratchet" can be developed if the pipe moves and create a void, then possibly the soil will collapse filling that void. During "cool down" the pipe will not go back to it's original position because it will be restraint by the soil that fills the void, and maybe the soil that collapse is stiffer than the original soil. Then as the pipe is expanding in only one direction the movement is accumulated. This is only a "wild guess" and only one of the "many possibilities"....If the pipe moves 2 meters this will create a huge force and maybe this is the cause why the pipe goes up above ground...Again this is only one of the "many possibilities"....


Cheers to all,