Construction of Mukaikogane stormwater trunk line crossing under the railroad track at 23k970m between Kitakogane and Minami-Kashiwa

Construction details High-density slurry type pipe jacking method with compatible type for underground obstruction
Method Milling mole method
Completion date Jul. 2017
Location of Construction Kashiwa city, Chiba Prefecture
Ordering party East Japan Railway Company
Pipe diameter φ1500㎜
Distance 34.068m
Type of soil Cohesive soil
Gravel size

Work summary

Nominal diameter φ1500㎜
Distance of pipe jacking 34.068m
Type of soil Cohesive soil
N value 0~5
Percentage of gravel -
Maximum gravel size -
Groundwater level GL-2.3m
Overburden 2.3m
Underground obstacles Many wooden stakes within 3m below the railroad track
Construction period Apr. 2017~Jul. 2017(Daytime work)

At the planning stage, the milling mall construction method was selected as an insurance method because there are many wooden piles under the old two lines out of the four lines.
For a while after launching, a small amount of wooden piles and concrete debris were excavated, and it was possible to excavate as usual. However, TBM encountered an unexpected obstacle 1.5m in front of the reception shaft and the cutter locked. So we used a telescopic jack to cut 300mm and was able to pass through obstacles and reach it safely.
As a result, I think we were able to reach it by adopting the milling mall method.

Discharged metal pieces

Discharged metal pieces