Soil/Geosynthetic Interface Strengths from Torsional Ring Shear Tests

Torsional ring shear tests were conducted to investigate Soil/Geosynthetic Interface Strengths of various geomembranes. A selection of seven smooth and three textured geomembranes (10 total) that can be factory fabricated were sheared against two soils to investigate the range of soil/geosynthetic interface strengths. The two soils are: (1) a clayey glacial till; and (2) Ottawa fine sand. Smooth PVC and both smooth and textured HDPE geomembranes were also tested so the fabricated geomembrane interface strengths could be compared to previously published interface strengths and commonly used geomembranes. The effect of texturing and material properties on shear strength and soil interaction are presented herein and compared with existing interface strength values. To facilitate the testing, programmable video cameras were used as a data acquisition system.