) Every 3 meters of depth, monitor the verticality/angle of the pile with a level or an angle ruler respectively, and connect the casing with welding according to the drawing until it reaches the stone surface or the required depth.
) Monitor the perpendicularity / angle of the pile with a water level gauge or an angle gauge every 3M depth, and use burning welding to barge the casting according to the drawing until it reaches the stone surface or the required depth.
B) Every 3m depth, monitor the verticality/angle of the pile with a level ruler or an angle ruler, and barge casing by welding according to the drawing until it reaches the stone surface or the required depth.