Cyclic shear stress degradation and post-cyclic behaviour from sand–steel interface direct shear tests

Abstract

The sliding interaction between sand and structural materials is involved in many geotechnical applications and is particularly important for the derivation of the shaft capacity of piles. Such interaction develops principally at the interface between the sand mass and the structural surface, and the comprehension of such interaction can be analysed through soil–structure interface tests. In particular, by using a modified version of the interface direct shear apparatus, that is, the constant normal stiffness direct shear apparatus, the friction characteristics of the interface and the role of the soil deformability on the experimental results can be studied. This paper focuses on the stress degradation occurring in these types of tests when cyclic loading is applied on sand–steel interfaces. Also, the post-cyclic response is analysed and compared to the response under monotonic conditions.Key words: interface, sand, shear stress, cyclic loading, stress degradation.

Physical Modelling of Geotechnical Structures in Ports and Offshore

“…If the behaviour of the superstructure can be relatively easily modelled the main difficulties are related to the soil response. Stress and strain level effects on the soil characteristics together with mobilization and accumulation of water pressures in a granular material subjected to cyclic or dynamic loading should be analyzed [26]. The problem is how to consider together the physical modelling of the structure, subsoil and their interaction.…”

Influence of Dilation on the Strength of Sand – Steel Interfaces

“…The stress-strain-displacement response of interface plays an important role in the behaviour of deep foundations, retaining walls and reinforcement of soils, which was extensively investigated experimentally and theoretically [1][2][3][4][5][6][7][8][9]. The mechanical behaviour of interfaces is a function of solid material roughness; soil state and stress level [10][11][12][13].…”

Post-Cyclic Behavior of Granular Soil- Structure Interface Direct Shear Tests

“…The main characteristic of cyclic interfaces under CNS condition performed by either direct shear or simple shear tests is the significant degradation in normal stress acting on the interface as a result of the gradual contraction. Consequently, the degradation of shear stress can be found ( [1], [4], [5], [8], [9], [14]). In case of shear stresscontrolled tests, the significant degradation of normal stress as a result of the progressive contraction accompanied with N brought the mean cyclic stress ratio ( cm ) defined as the ratio between mean cyclic shear stress ( cm ) and mean cyclic normal stress ( n cm ), i.e., This paper presents some of experimental observations carried out from a series of direct shear tests of sand and rough surface structure under constant normal stiffness (CNS) condition with a large number of small cycles in terms of shear stress.…”