Effect of stress paths on the behaviour of sand–steel interfaces

Abstract

An apparatus has been developed to carry out two- and three-dimensional tests on interfaces between soils and structural materials. The soil container facilitates both the sliding displacement at the interface and the shear deformation in the soil mass. The apparatus has the capability of maintaining the normal stiffness constant during shearing. In constant normal stiffness tests, the normal stress is adjusted continuously by a computer-controlled system to keep the normal stiffness at a desired value. In addition to constant normal stiffness tests, conventional types of tests can be performed during which the average normal stress acting on the interface is kept constant. In all types of three-dimensional tests, the interface can be subjected to tangential loading in two orhtogonal directions simultaneously. Experiments were conducted to study the two- and three-dimensional behaviour of an interface between a dense sand and a rough steel surface under both constant normal stress and constant normal stiffness conditions. The influence of various stress paths on the stress–displacement relations and shear strength characteristics of the interface are investigated. The experimental results indicate that the coefficients of friction corresponding to the resultant peak and residual shear strengths are independent of stress paths. The shear stress – tangential displacement and volume change behaviour of the interface, however, are significantly influenced by stress paths. Key words: interface testing, simple shear, peak and residual shear strength, three-dimensional, constant normal stiffness, stress path.

Constitutive description of interface behavior including cyclic loading and particle breakage within the framework of critical state soil mechanics

“…For illustration purpose, the monotonic simple shear tests on sand-steel interface in Evgin and Fakharian [40] and the cyclic ones in Fakharian and Evgin [7] were used to demonstrate the model calibration procedure. From the two papers, it is realized that the sand and the steel were the same in the tests; hence, one set of model parameters would be adequate.…”

“…The critical state parameters and e i 0 are identified with the ultimate normal dilation (or contraction) of the interfaces as well as the initial void ratio e in and the thickness of the interface t. For the illustrating interface, the initial void ratio of the sand reported in Evgin and Fakharian [40] and Fakharian and Evgin [7] was used, whereas the thickness of the interface was obtained using the D 50 of the sand [25]. The ultimate vertical displacements in the three monotonic constant normal stress tests were then used to calculate the critical state void ratios using Equation (20) in Liu et al [25], which subsequently were substituted into Equation (11) to calculate and e i 0 as shown in Table I.…”

“…Calibration of the model parameters for the experimental results in Evgin and Fakharian [40] and Fakharian and Evgin [7]: (a) monotonic test and (b) cyclic test. [40] and Fakharian and Evgin [7] The monotonic simple shear tests on sand-steel in Evgin and Fakharian [40] and the cyclic ones in Fakharian and Evgin [7] were conducted using the proposed model. The calibration of the model parameters was already introduced in the previous section.…”

Experimental research on adfreezing strengthsat the interface between frozen fine sand and structures

“…Several researchers [1][2][3][4][5][6][7][8][9] did some experimental and numerical studies on the general behavior of geomaterial interfaces. However, at present, research results on adfreezing strength at the interface between arti cially frozen soil and structures are relatively few and basic.…”

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].…”