Nachweise in Richtung der Rohrachse: Verformung am Druckübertragungsring beim Rohrvortrieb
The animation shows a jacking with a starting- and a target shaft, a microtunnelling machine and the single pipes presented in a condensed way. Here the rectangle in the illustration of the pipe string marks the pipe joint looked at, which consists of the two end faces of the pipe und the pressure transfer ring lying between them. The pressure transfer ring is presented in an exaggerated way regarding its thickness. The particular maximum stress is marked by a green arrow in the cross section of the pressure transfer ring and is copied into a corresponding diagram during jacking.
Here the stress distribution is dependent on the jacking force, the angular deflection of the pipes to one another and the particular plastic deformation of the pressure transfer ring already impressed before. When driving from a straight to a tight curved path first a trapezium appears and after that a triangle over the entire cross section if we start from a rectangular stress distribution. If the angular deflection increases further, a gaping joint and a corresponding triangular stress distribution, but which does no longer stretch across the entire cross section, develops. Since the integration of the stress distribution over the pressure-transferring area is equal to the jacking force, correspondingly larger stress peaks result especially at the outer area. During jacking the pressure transfer ring rounds off, becomes overall thinner and correspondingly harder.