Performance Study of Segmental Tunnel Liners Under Thrust Jack Loads

REU: Underground Infrastructure REU  | AUTHOR: Constantine Patmanidis – Lehigh University

MENTORS: Ziyan Ouyang, Spencer Quiel, Clay Naito – Lehigh University

ABSTRACT

Precast segmental tunnel liners, installed via tunnel boring machines or TBMs, have become increasingly used in modern tunnel construction. The performance of the circumferential joints due to in-plane loading will influence the response of the liner to other types of loading during tunnel operation. This study evaluates the capacity of the circumferential joints for thrust jack loading. Six tests have been conducted to investigate the effect of conventional reinforcement bars, eccentricity, loading and boundary conditions (double- or single-point loading) during the tunnel liner segment installation, with a thrust load that goes up to five million pounds. All the segments, when subjected to single point loading that went up to five million pounds, have significant damage, especially the segments that have only been reinforced with steel fibers. Their ultimate capacity is significantly lower than the segments reinforced with steel fibers and steel bars, and coupled with a more brittle failure mode.

AUTHOR BIOGRAPHY

Constantine Patmanidis is a rising junior at Lehigh University pursing a B.S. in civil engineering, and is a student in the P.C. Rossin College of Engineering and Applied Science. This summer he was involved with conducting a performance study of segmental tunnel liners’ response to simulated tunnel boring machine thrust jack loads. Full scale testing for this project was conducted at Lehigh University’s Fritz Lab. The majority of small-scale testing and analysis for this project was conducted at ATLSS (Advanced Technology for Large Structural System), a National Engineering Research Center on Lehigh’s mountaintop campus. Constantine is planning to continue with this research in the future by conducting a joint flexural study of segmental tunnel liners.