When designing a shield tunnel, there is often a need to carry out mechanical tests on tunnel lining joints to obtain joint stiffness. As tunnel excavation goes deeper, the moment and axial force acting on the lining segments increase, which requires a more rigid backup frame and a stronger foundation for the traditional testing setup. A new testing setup, named as Compression Steel Butterfly (CSB), was developed. CSB is biaxially symmetric in geometry, consisting of two steel frames connected by horizontal tensile pulling rods passing through the mounting holes of hollow hydraulic ram jacks. Using CSB, different combinations of axial force and bending moment can be effectively and conveniently imposed on the testing segments by varying the magnitudes of pulling force of each pair of pulling rods. Since the jacking forces are self-balanced, there is no need for a strong backup frame. A series of finite element simulations were carried out to validate the loading capacity and correctness of load transmission for the new testing setup. It is shown that the axial force and moment obtained in numerical simulations agree well with the theoretical values.

LOKASI: Ruang Koleksi Umum
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