Study on friction characteristic around shield machine using ring shear apparatus.
In shield tunnelling, the frictional resistance between the shield and the ground, that between the segment and the grease are the predominant factor of jack thrust. However, there is no test results about the friction characteristics around the shield. Therefore, this research aims to search the friction characteristics on the circumference of the shield by the ring shear test.
The friction force between the steel and the sample represents the friction force between the shield and the natural ground, and the friction force between the concrete and the grease represents the friction force between the segment and the grease.
The followings were made clear by this research.
1j Peak intensity :
a) Kaolin : tanΣr/tanΣp=0.56
b) Sand : With no clear peak value
2j Shear speed : no influence on friction force
3j Steel coarseness:
a) Kaolin : Coarse >: Common = smooth
b) Sand : Coarse >: Common >: smooth
4j Intervention :
a) Kaolin : Water = nothing >: muddy water
b) Sand :Can not examine the results at the same conditions since the surface
coarseness become smooth
5j Soil-steel :
a) Kaolin : Σ13.2
b) Sand : Σ22.5
6j Grease :
a) Grease-concrete : Σ6.1
b) Grease-steel : Σ6.5