Abstract: A process for planting a row of cement piles on the bed of a river includes the steps of (1) placing a vertical guide member of a U-shaped cross-section on the bed, the guide member including two parallel side plates having a width larger than that of the side surfaces of the piles, and a web interconnecting the side plates, the web having a vertical lower section and an inclined upper section; (2) sliding downward the first cement pile over the inner surface of the web until the first cement pile is planted on the bed; (3) inserting downward the second the cement pile into a space between the inclined upper section of the web and the first cement pile; (4) pushing downward the second cement pile, until the second cement pile is planted on the bed, with the result that the guide member is impelled by the second cement pile to move to a position which is in line with the first and second cement piles, and that a vertical coupler hole is defined between the tongues of the second cement pile and between the groo