Assessment of shear strength for clay liners using a dynamic probe

Abstract

Liner-cover layers are top layers normally placed when closing landfill sites. The top layers are commonly subjected to the direct influence of moisture, temperature changes, and erosion. This study proposed the use of a dynamic cone penetrometer as a quick tool to assess the shear strength and density of sand-clay cover liners. Poor areas indicating low shear strength and dry density need to be investigated and identified. Changes in moisture content and dry density affect the soil compressibility and shear strength parameters. A lightweight dynamic probe was found to give reliable shear strength measurements when assessing bentonite sand mixture materials. The impact of the moisture content on the profile of penetration was established and a bilinear relationship between the cone penetration and moisture content is shown. Laboratory fall cone tests were conducted to verify the trends of penetration and the influence of dry density. It was found that a linear function can be established within the wet of the optimum zone of the compaction curve. The tests conducted support the effectiveness of using dynamic cone penetrometers for measurements and evaluation of shear strength and dry density for sand clay cover liners. This will pave the way for using a quick tool for the assessment of compaction uniformity and shear strength of sand clay cover liners.

Keywords

• Shear strength
• Cone penetrometer
• Liners
• Sand-clay mixtures