After passing the intermediate shaft about 100m after launching, TBM encountered the first obstacle about 80m from there, and encountered the obstacle 6 times in the section of about 30m.
No obstacles appeared in the remaining 222m.
The geology was a composite ground of reclaimed gravel, sand and cohesive soil. The steel sheet pile type III, which is an obstacle, was left behind during the manhole construction of the sewage pipe that runs parallel to the upper part of the pipeline that was constructed this time.