Takeshi Kamei

Application of Gypsum Waste Plasterboard and Waste Plastic Trays to Enhance the Performance of Sandy Soil

This paper presents the results of a research project that evaluated the use of recycled gypsum obtained from waste plasterboard along with strips of waste plastic trays to enhance the performance of tested soil. Recycled gypsum was used as a stabilizing agent for stabilized soil to improve the compressive strength, whereas the waste plastic trays were used to improve the tensile strength. The effects of waste gypsum content, size, aspect ratio and waste plastic trays content were investigated to determine the mechanical behavior of soil treated with such waste materials. Experimental test results showed that unconfined compressive and splitting tensile strengths increased with increasing waste gypsum content. The increase in waste gypsum has a more significant effect on the unconfined compressive strength than on the tensile strength. Adding strips of waste plastic trays to samples treated with waste gypsum enhanced the splitting tensile strength. The size, aspect ratio and content of waste plastic trays have significant effect on the enhancement of soil strength.

Evaluation of undrained shear behaviour of k0-consolidated cohesive soils using elasto-viscoplastic model

Abstract This paper presents a simple procedure for determining the soil parameters and the analytical results of the undrained shear behaviour of K 0 -consolidated cohesive soils using elasto-viscoplastic model proposed by Sekiguchi and Ohta. Comparisons were made between experimental data and model simulations concerning the undrained triaxial compression and extension loadings controlled with the different strain rate, for the purpose of checking the reliability of the analytical results obtained from the adopted model and soil parameters introduced in the present paper. Several strain controlled undrained triaxial tests of K 0 -consolidated cohesive soils are simulated and reasonable agreements have been obtained between the observed and the computed results of the undrained shear behaviour of K 0 -consolidated cohesive soils. The analytical results obtained by the present methods are found to be reasonable and it is encouraged to use the presented methods in geotechnical engineering practice.