Numerical analysis and field test on performance of steel-fibre- reinforced concrete segment in subway tunnel.

To investigate the mechanical behaviors of steel fibre reinforced concrete (SFRC) segments which are firstly used in the test section of the Shanghai Rail Transit Project Line 6, and to propose some useful suggestions for design and construction, a numerical analysis and field test are conducted. The contents of this study involve: (1) the behaviors of the segments against the jacking force, (2) the occurrence and development of cracks, the distribution of stress and strain of segment body, and (3) the distribution of stress and strain in circumferential joints of lining. The results show that safety against the jacking force of shield and the distribution of tensile strain in segment body and joint meet the requirement of design and construction. No cracks have been found in segments under the construction load. This indicates that the steel fibre provides the concrete of the segment with an improved crack resistance. It should be noticed that, although there is no cracks, the maximum tensile strain of rabbets of circumferential joints is much larger than the critical strain of the concrete. It is suggested that the rabbets should be reinforced in design.
To investigate the mechanical behaviors of steel fibre reinforced concrete (SFRC) segments which are firstly used in the test section of the Shanghai Rail Transit Project Line 6, and to propose some useful suggestions for design and construction, a numerical analysis and field test are conducted. The contents of this study involve: (1) the behaviors of the segments against the jacking force, (2) the occurrence and development of cracks, the distribution of stress and strain of segment body, and (3) the distribution of stress and strain in circumferential joints of lining. The results show that safety against the jacking force of shield and the distribution of tensile strain in segment body and joint meet the requirement of design and construction. No cracks have been found in segments under the construction load. This indicates that the steel fibre provides the concrete of the segment with an improved crack resistance. It should be noticed that, although there is no cracks, the maximum tensile strain of rabbets of circumferential joints is much larger than the critical strain of the concrete. It is suggested that the rabbets should be reinforced in design.