Modified direct shear apparatus to perform small-scale pullout tests of geosynthetics

• Grant number: 15/07735-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2015
• End date: June 30, 2016
• Field of knowledge: Engineering - Civil Engineering - Geotechnical Engineering
• Principal Investigator: Fernando Henrique Martins Portelinha
• Grantee: Leonardo Vinícius Paixão Daciolo
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Reinforced soil walls using geosynthetics has been largely used as practical solutions in geotechnical engineering in view of the technical (versatility, flexibility and functionality) and economical advantages. In designs, the shear interface strength between soil ans reinforcement is analyzed to assure the acceptable performance avoiding that the reinforcement do not be pulled or slidden from the soil mass. Tests to assess the shear interface strength required for design analyses are interface direct shear tests and pullout tests. In Brazil, there is the lack of standards of procedures for these types of tests, which do not occur in European or North American countries. In fact, the geosynthetic pullout tests are intensively used for better providing the assessment of interface shear behaviour and for calculation of anchorage length in reinforced soil walls. Pullout tests has been performed by the use of large pullout apparatus demanding relatively high costs and technical difficulties in construction and in parameters controlling. In regards of these facts, this work intends to evaluate pullout tests performed though small-scale apparatus reducing costs and facilitating the assessment of the interface shear strength between soil and geosynthetics. For this, a conventional direct shear apparatus will be adapted to perform small-scale pullout tests of geosynthetics, whose dimensions will be significantly lower than those reported at the literature. Results will be compared to other reported in literature which were performed by the use of large pullout apparatus. In this research, parameters that affect the interface shear strength will be evaluated, as type of soils, geosynthetics and soil conditions. (AU)