Enhancement of soil-geogrid interactions in direct shear mode using attached elements as anchors

• Published in: European journal of environmental and civil engineering 2020-07, Vol.24 (8), p.1161-1179
• Main Authors: Abdi, Mahmood Reza, Safdari Seh Gonbad, Mahdi
• Format: Article
• Language: English
• Subjects: anchor; direct shear; geogrid; Geosynthetic; grading; interaction
• ISSN: 1964-8189; 2116-7214
• DOI: 10.1080/19648189.2018.1454861

Soil reinforcement employing geosynthetics is significantly influenced by interactions which are governed by friction and adhesion at interface. To enhance interactions at soil-geogrid interface under direct shear conditions, effects of attaching elements as anchors to reinforcement has been evaluated. A well and poorly graded sand, one geogrid type, anchors with three different size and clamping lengths of 2, 4 and 6 cm from shear surface were used. Samples were prepared with a relative density of 80% and tested dry under normal pressures of 12.5, 25 and 50 kPa using large direct shear test. Factors investigated included soil grading and particle size, anchor size and anchorage length together with normal pressures. Results shows by attachment of anchors to upper geogrid surface, shear resistance to failure is significantly enhanced with increase in normal pressure and anchor size. This is attributed to soil-anchor friction at interfaces, mobilisation of soil passive resistance in front of anchors and tensile strength of reinforcement. Non-uniform sand having larger and angular particles resulted in more effective interactions with geogrid and anchors at interfaces and resulted in greater resistance to shear failure under direct shear loading. Soil particle size and anchorage length were found to be less influential factors on soil-geogrid interactions.