Mechanical Behavior of Interface between Composite Geomembrane and Permeable Cushion Material

Abstract

An accurate description of composite geomembrane-cushion interface behavior is of great importance for stress-deformation analysis and stability assessment of geomembrane surface barrier of rock-fill dam. A series of direct shear tests were conducted to investigate the friction behaviors of interfaces between composite geomembrane and two different permeable cushion materials (crushed stones and polyurethane mixed crushed stones). The shear stress-displacement relationships of the two interfaces show different characteristics and were described by the nonlinear-elastic model and nonlinear-elastic perfectly plastic model, respectively. Then the two models were implemented into the Fast Lagrangian Analysis of Continua in Three Dimensions (FLAC3D) procedure correctly. By verification of a numerical example, numerical calculation results showed a good agreement with the theoretical solutions and test results.

Stress and Deformation Property of Geomembrane Surface Barrier for High Rock-fill Dam

“…To obtain the parameters and relation curves between shear stress and shear displacement of composite geomembrane-cushion interface, direct shear tests of the interface was conducted specifically [10] . Figure 2 shows the relation curves between shear stress and shear displacement of composite geomembrane-cushion interface.…”

“…The calculation parameters of concrete-soil and concrete-rock interface elements are shown in Table 2. The elastic modulus and Poisson's ratio of geomembrane were selected from the tensile test results [15] ; interface parameters of geomembrane-cushion interface element were selected from direct shear test results [10] . The calculation parameters of the geomembrane element and geomembrane-cushion interface element are shown in Table 3.…”

Model Test on Mechanical and Deformation Property of a Geomembrane Surface Barrier for a High Rockfill Dam

“…After two days of curing of cushion layer, the composite geomembrane is directly laid onto the surface of the polyurethane bonded aggregate cushion. The sheer strength of the interface between the filament geotextile on the surface of the composite geomembrane and polyurethane bonded aggregate cushion maintains its stability [33]. (4) Protective layer: The protective layer is composed of situ-cast plain concrete and has a thickness of 20-30 cm.…”