Influence of anisotropic stress states on soil-structure interface behavior: a new experimental approach in a modified hollow cylinder apparatus

To determine the influence of soil-structure interface behavior on the bearing capacity and deformations of geotechnical structures, suitable testing methods capable of simulating in situ conditions are required. This article introduces a novel test method for soil-structure interface tests. A hollow cylinder triaxial device is modified to conduct interface tests with four independent control variables. This enables investigations of the influence of different anisotropic stress states on the contact shear behavior of granular material. First test results on Karlsruhe fine sand are presented with a variation of the lateral normal stresses acting on the plane orthogonal to the shear (i.e., contact) plane. These tests are conducted in two modes: in mode A long samples (d$_o$ = h) are used whereas in mode B short samples (2(d$_o$ − d$_i$) = 1/h) are used. The results of the test series in mode A show that the failure occurs either in the soil (on the plane with the highest ratio of the shear and normal component of the stress vector τ/σ$_N$) or on the contact plane (where the shear strength is reduced). The failure in the test series with mode B is restricted to the horizontal plane due to sample geometry. ... mehrThe findings will be utilized in the future to test and develop various modeling methods for soil-structure interfaces.