Local splitting and crushing behavior under TBM hydraulic jacks

During the lining construction process, high concentrated thrust jack forces are introduced in the segments by the Tunnel Boring Machine (TBM) leading to both high compressive stresses under the thrust shoes that can provoke a concrete crushing and tensile transversal stresses; the latter can cause cracks and, eventually, a splitting failure. In order to investigate the main mechanisms involved during either splitting or crushing failure, specific experimental tests on prismatic concrete specimens loaded by concentrated axial forces were designed. The specimens were cast using Steel Fiber Reinforced Concretes (SFRCs). The experimental results were compared with the ones obtained from specimens reinforced only by means of traditional steel rebars.