[Geotechnical Engineering]

Zhang, Z. Y., Jin, X. G., Luo, W. Mechanical responses of shotcrete specimens in direct shear tests[J]. Construction & Building Materials, 2018, 188: 305-313.

Keywords: Shotcrete Material; Shear Response; Direct Shear Test; Loading Path; Shear Strength

Abstract:

In this study, the direct shear tests under constant normal stress condition (CDST) and unloading normal stress condtion (UDST) were conducted to investigate the shear responses of shotcrete specimens, with using a self-designed test scheme and an auxiliary device on a rock compression-shear test system in Chongqing University, China. The shotcrete specimens were of strict preparation complying with the Chinese Standards. A total of eighty five shotcrete cubic specimens (100 × 100 × 100 mm3) were tested. Results from this study show that the shear strength of shotcrete specimens (C25) is accorded with the Mohr-Coulomb criterion (M-C), with the cohesion of 5.1 MPa and the internal friction angle of 39.4° obtained. The loading path, the initial normal stress (INS) and the initial shear stress (ISS) have an influence on both displacement and shear strength of the shotcrete specimens. For instance, a higher INS or ISS leads to a higher failure normal stress and a smaller unloading amount. Compared with the results from the CDSTs, the cohesion of shotcrete specimens has a reduction of 1.746 MPa while the internal friction angle increases slightly in the UDSTs. In addition, the effects of INS and ISS on the initial micro-damage of shotcrete specimens are also investigated.