Damage Analysis of Geomembranes through a 3D Optical Profilometer: Fid-Bau Portal

Damage Analysis of Geomembranes through a 3D Optical Profilometer

Vangla, Prashanth / Boro, Ishan / Gali, Madhavi Latha

The mechanisms governing the shear behaviour of sand and sand-geomembrane interfaces is studied by carrying out large scale symmetric loading direct shear tests on three sands of different sizes with similar morphological characteristics and a smooth high density polyethylene geomembrane. To focus on the effect of particle size on the shear behaviour, the morphological properties of sand particles, measured from microscopic images, were kept same. Surface topographical profiling of the geomembranes before and after interface shear tests was carried out to understand the extent of indentation due to shearing along the interface. The representative samples of smooth geomembranes after tests with three sands of different sizes at one particular normal stress were selected for damage analysis/surface roughness measurements through 3D optical profilometer. 3D contours of surface roughness of the geomembrane before and after the tests are presented and compared. Interface shear strength was observed to hugely depend upon the effective contacts formed on the surface of the geomembrane, which are a function of the number of particles in contact and the depth of the grooves formed by these particles on the surface of the geomembrane.