Suction influence on small strain stiffness of a lateritic soil

• Grant number: 10/17214-5
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2011
• End date: March 31, 2013
• Field of knowledge: Engineering - Civil Engineering - Geotechnical Engineering
• Principal Investigator: Orencio Monje Vilar
• Grantee: Orencio Monje Vilar
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

The differences between soil stiffness obtained from laboratory tests and field measurements took attention of many investigators in the last 40 years. The evidences that ground strains at many engineering structures are in a small and a very small ranges and also the limitations of techniques to test soils in such conditions lead to the development of field and laboratory techniques based on dynamic loading. Two of these techniques are the bender elements and the resonant column, which can accurately define the stiffness properties of soils in a small strain range. Particularly, the use of bender element method is recent and has increased due to the simplicity of both performing the tests and calculating the maximum shear modulus and minimum damping ratio of the soils. The stiffness properties of saturated soils obtained via bender elements have been the focus of many studies; nevertheless, there still is little information about the use of this technique to test unsaturated soils. Motivated by this lack of information, this research aims to study the influence of some variables, such as suction, confining pressure and strain range on the stiffness of an unsaturated lateritic soil, which covers a wide area of Sao Paulo State. The behavior of undisturbed and compacted samples of this soil will be analyzed via bender elements tests and triaxial compression tests with local strain gauges. As a result, this research will contribute to the knowledge of geotechnical properties of Sao Paulo State's typical soils by enhancing the understanding of its stiffness properties. (AU)