Stiffness of granular soils under long-term multiaxial cyclic loading

Geotechnical infrastructures may be subjected over their lifetime to long-term loading cycles of varying amplitude, frequencies and direction as a result the combination environmental operational processes. Soil elements surrounding foundations these geotechnical systems are in turn complex six-dimensional stress paths, invariably involving rotation principal axes. Changes soil's mechanical properties can lead changes overall structure dynamics, well an accumulation irreversible deformations. However, evolution response stiffness under cyclic scenarios is neither known nor adequately understood. In contrast conditions imposed by standard laboratory tests, this research used hollow-cylinder torsional apparatus (HCTA) explore small-strain granular soil multiaxial drained (up about 6 × 10 5 ). Granular samples were stages regular low-amplitude at different anisotropic levels interspersed periodic large-amplitude loops. A high-resolution local strain measurement system was employed determine vertical Young's modulus shear modulus, both attained HCTA testing. It found that cycles, continuous axes, caused degradation up 20% elastic properties. Within 4 2 degraded stiffnesses reached stable value, which maintained least 8 cycles. The more pronounced for than soil.