Shear Strength and Consolidation Yielding Stress of Pleistocene Clay Found at Izumi-Hill of Osaka District

Abstract

Shear strength and consolidation yielding stress of heavily overconsolidated Pleistocene clay found at Izumi-hill of Osaka District are presented. Unconfined compression, field vane and' various kinds of direct shear tests were conducted for evaluating the shear strength, while-standard and strain controlled oedometer tests were carried out for determining the consolidation yielding stress. It was found that unconfined compressive strength is about half of field, vane and direct shear strengths, and this difference was suggested to be caused by that extensive failure at a weak point takes place in most case in unconfined compression test. It was also-found that field vane test is an effective tool for evaluating the shear strength of this kind of material. Consolidation yielding stress determined by standard and strain controlled oedometer tests are discussed as related to the undrained shear strength obtained from direct shear test. It was strongly suggested that the consolidation yielding stress should be determined by strain controlled oedometer test and the clay investigated is fundamentally classified into normally consolidated aged clay.