Abstract: A tunnel-like formwork comprising two side shuttering panels connected together at their upper edges by a flexible upper shuttering panel. The side shuttering panels are provided with wheels. Inside of the said formwork, a framework structure is disposed, comprising at least four upright members to the upper ends of which four arms are hingedly connected, the said arms being in turn hingedly connected at their lower sides to one end of four inclined struts elements the other end of which is slidingly guided into a slide guide formed in the said upright members. The said upright members are provided at their lower ends with retractable bearing feet.