Experimental study of the overconsolidation and saturation effects on the mechanical characteristics and residual strength of Chlef river sandy soil
This paper presents a laboratory study of the influence of the saturation evaluated in terms of Skempton´s pore pressure coefficient (B) and overconsolidation ratio (OCR) on the behavior of Chlef sand. The study is based on drained and undrained triaxial compression tests which were carried out for Skempton´s pore pressure coefficient varying between 13 and 90% and OCR varying between 1 and 8. Tests were conducted on medium dense sand samples having an initial relative density Index Id = 0.5 at an effective stress of 100 kPa. The paper is composed of two parts. The first one presents the characteristics of the sand used in this study, the second provides an analysis of the experimental results and discusses the influence of Skempton´s pore pressure coefficient (B) and OCR on the mechanical characteristics of the sand. The tests show that the increase in the Skempton´s pore pressure coefficient (B) reduces the soil dilatancy and amplifies the phase of contractancy and reduces the frictional and characteristic
angle of the sand. The increase of OCR improves the stiffness of sand and accelerates the appearance of dilatancy; and increases frictional and characteristic angle of the sand. Moreover, the present study focuses on the effect of saturation and overconsolidation on the residual shear strength of sand.
Anisotropy in Elastic Deformation of Granular Materials.
Inherent and stress state-induced anisotropy in the elastic deformation properties of granular materials were investigated experimentally. Both axial and lateral principal strains of large square-prismatic and small solid cylindrical specimens were measured locally. Very small strain-amplitude cyclic normal stresses were applied in the vertical and horizontal directions at various isotropic and anisotropic stress states. Elastic deformation properties are inherently anisotropic with the Young's modulus being larger in the vertical direction than in the horizontal direction at isotropic stress states. The Young's modulus is stress state-dependent, becoming more anisotropic as the stress state becomes more anisotropic. The elasticity is of hypo-elastic type. Deformations do not become totally elastic even after the application of a large number of stress cycles of relatively large amplitude along a fixed stress path.
The Inca Occupation of the South Coast of Peru
like the others, however; it forks into several nearly parallel ravines of which the largest are Huayuri, Rio Grande-Palpa, Ingenio (called Collao in ancient times), Nasca proper (the ancient Caxamarca), Taruga, and Poroma. Due to peculiarities of the local topography, the irrigated areas in Ica and the ravines of Nasca are located inland, at the foot of the mountains, rather than at the mouths of the rivers as is more usual in Peruvian coastal valleys. No sharp natural or cultural boundary separates the valley of Chincha from the valleys of Cafiete (ancient Huarco and Runahuana), Asia, and Mala, the next valleys going up the coast to the northwest. At the other end of the area we are considering, however, there is a sharp break; beyond Yauca the Andean foothills reach out to the sea, natural conditions are quite different, and there are important differences in the archaeological picture as well. The historical sources which mention the south coast are not particularly helpful, except in so far as they provide us with a few dates. To begin with, no chronicler gives an explicit account of the political organization of the south coast at the time it came into contact with the Incas. It can, perhaps, be inferred from Cabello Balboa's statements about common policy toward the Inca invaders that there was some sort of political connection between the valleys of Mala, Cafiete, and Chincha, but the connection need have been no more than a temporary military alliance. Cabello makes no mention at all of Pisco. The valleys of Ica, Nasca, and 125