Toshihiro@SAKURAI STUDY ON INFLUENCE OF CUSHION RING ON PIPE BY PROTOTYPE TEST OF PIPE JOINT Mitsutaka SUGIMOTO Development of technology on long distance jacking and jacking at sharp curve is expected recently, in pipe jacking method. To solve these problems, it is necessary to carry out the theoretical approach to jacking mechanism taking account of the whole of pipes and TBM, since all of the pipes are advanced with the TBM in case of pipe jacking method. Furthermore, acting load on pipe should be studied, based on the above approach. Therefore, the prototype test on pipe joint was carried out to make clear the influence of cushion ring on pipe during jacking. Based on the above test, this paper reports the pipe joint behavior and the generating axial strain in the pipes due to jacking along straight and curved alignment.