Study on Thrust Estimation in Pipe-Jacking Method

Mitsutaka SUGIMOTO

The conventional model for thrust estimation in pipe-jacking method does not consider the gap between the ground and tunnel. Therefore, the conventional model cannot evaluate the influence of over-cutting, which has strong influence on frictional resistance and adhesion around pipe. As a substitute, it adopts loosening earth pressure and modulus of thrust reduction for each ground conditions.
To overcome the above problems, this study aims to develop a new analysis model by using full ground springs model that can take over-cutting into consideration. And the proposed model for thrust estimation is examined by verifying an analysis result from the viewpoint of mechanics.
As a result, it was made clear that the proposed analysis model can express the ground pressure distribution, the acting stress on pipe and the stress state of pipe in pipe-jacking method reasonably. Finally, It can be said that the newly developed analysis model can estimate the thrust in pipe-jacking method.