The cyclic behaviour of soils and effects of geotechnical factors in microzonation

Geotechnical site conditions that can be very different due to changes in t hickness and properties of soil layers, depth of bedrock and water table ar e among the main factors controlling earthquake characteristics on the grou nd surface. Soil layers subjected to cyclic stresses may lead to degradatio n of stress-strain and shear strength properties. The laboratory tests were conducted to evaluate the changes in the stress-strain and shear strength characteristics in terms of threshold cyclic shear stresses and cyclic yiel d stress. The effects of local site conditions are assessed based on geotec hnical site conditions and earthquake source characteristics. (C) 2001 Publ ished by Elsevier Science Ltd.