Abstract: A method and an apparatus for advancing cylindrical bodies. More than two underground cylindrical bodies are laid in longitudinal alignment with thrusting jacks disposed between them. A connecting member is arranged to pierce through them. A fastener is attached to one end of the connecting member while an advancing jack arrangement which has a removable-and-attachable fastener is attached to the other end of the connecting member. A suitable anchor body is disposed in front of the alignment of cylindrical bodies. Between the anchor body and each of the cylindrical bodies, there is provided a fixing member which pierces through them. Removable-and-attachable fasteners are disposed between the fixing member and the cylindrical bodies to interlink them for moving them forward underground one after another.

Abstract: A method and an apparatus for advancing cylindrical bodies. More than two underground cylindrical bodies are laid in longitudinal alignment with thrusting jacks disposed between them. A connecting member is arranged to pierce through them. A fastener is attached to one end of the connecting member while an advancing jack arrangement which has a removable-and-attachable fastener is attached to the other end of the connecting member. A suitable anchor body is disposed in front of the alignment of cylindrical bodies. Between the anchor body and each of the cylindrical bodies, there is provided a fixing member which pierces through them. Removable-and-attachable fasteners are disposed between the fixing member and the cylindrical bodies to interlink them for moving them forward underground one after another.