Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2009.1036.1045KhazaieJ.AmirshahkaramiS.A.6200996In this study, change in behaviors occurring beneath
and around the foundation which caused by changes in foundation dimensions
is studied numerically, by taking into account the interaction between
earth and foundation. To do so, two dimensional and constant computational
models with constant domain under uniform distributed load for both large
and small foundation have been analyzed using ANSYS software, version
8.1. The results of this analysis clearly show that the earth beneath
and around small foundations is shearing and general failure mechanism,
which is the same as the predicted behavior and accepted failure mechanism
most researchers believe in. But, based on the results obtained from this
research, the earth located in the central areas as well as the earth
under the large foundations is mainly bearing compressive and comprehensive
stresses having hardening. Consequently, their endurance is gradually
increasing. Hence, the stress concentrations as well as the deformations
are directed toward this region. In case loading is constant, the regions
outside the foundation and beneath (the sides) bear unloading (localization).
While footing dimensions increase, rigid wedge angle will be increased
up to 90°. Thus, the failure mechanism in large foundations is local
and forming a resistant. Such resistance creates bearing column beneath
the foundation and punching effect which happens between the earths under
the vicinity of the foundation is clearly seen. Namely, if soil behavior
and properties change, the foundation geometry will change as well. So,
with regard to geometry increase and with the change in the behaviors
of the earth material, the stiffness matrix changes which is in the form
of coupled.]]>Amirshahkarami, S.A.,1978-2007Bowles, J.E.,1982Zhu, F., J.I. Clark and R. Phillips,2001Lee, J., R. Salgado and S. Kim,2005Katsutoshi, U., M. Kinya and M. Yoshito,1998Katsutoshi, U., M. Kinya, K. Osamu and N. Migitoshi,2001Khazaie, J. and S.A. Amirshahkarami,2007Shahkarami model).]]>Meyerhof, G.G.,1963Owen, D.R.J. and E. Hinton,1980Terzaghi, K.,1943Zienkiewicz, O.C. and R.L. Taylor,2000Zienkiewicz, O.C.,1991