Local splitting and crushing behavior under TBM hydraulic jacks

During the lining construction process, high concentrated thrust jack forces are introduced in the segments 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, a simplified analytical study is firstly presented on the two load configurations generally adopted in practice, namely the Line Load (LL) and the Point Load (PL). Based on this analytical study, experimental tests on Steel Fiber Reinforced Concrete (SFRC) specimens subjected to a LL configuration have been carried out. Experimental results indicate that the use of fibers significantly enhances the splitting bearing capacity, the ductility and can also alter the collapse from splitting to crushing.