Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2009.2544.2555JesmaniM.ShafieM.R.VilehR.S.122009914Present study examines effects of geometrical parameters of annular open trenches, such as depth and location, on active isolation of deep foundations in different clayey soil. Three dimensional Finite Element Analyses (FEA) with ANSYS software are employed to carry out a parametric study. The point to surface contact element for the nonlinearity state of the soil-pile interface as well as nonlinear Drucker-Prager soil behavior under full transient analysis has been utilized to attain more realistic results. In this research, the critical trench location for pile foundations is obtained based on the FE results. Also, a minimum trench depth of 0.5 times the pile length is the optimal depth to attain an ideal vibration reduction and construction of deeper trench is uneconomically. Lastly based on results, the contour plots for A_{rr} against trench depths and locations are presented for practical applications purposes. Simplified mathematical formulations based on the contour plots are derived to evaluate efficiency of a trench in active isolation system of deep foundation.]]>Adam, M. and O. Estorff,2005Ahmad, S. and T.M. Al-Hussaini,1991Ahmad, S., T.M. Al-Hussaini and K.L. Fishman,1996Al-Hussaini, T.M. and S. Ahmad,1996Al-Hussaini, T.M. and S. Ahmad,2000Amick, H. and M. Gendreau,2000Attewell, P.B. and I.W. Farmer,1973Beskos, D., G. Dasgupta and I.G. Vardoulakis,1985Beskos, D.E., G. Dasgupta and I.G. Vardoulakis,1986Beskos, D., K. Leung and I.G. Vardoulakis,1986Beskos, D.E., K.L. Leung and I.G. Vardoulakis,1990Beskos, D.E., K.L. Leung and I.G. Vardoulakis,1991Celebi, E.,2006Celebi, E., S. Fırat and I. Cankayac,2006Drucker, D.C. and W. Prager, 1952El Naggar, M.H. and A.G. Chehab,2005Haupt, W.A.,1977Kattis, S.E., D. Polyzos and D.E. Beskos,1999Kattis, S.E., D. Polyzos and D.E. Beskos,1999Lysmer, J. and Waas,1972Segol, G., P.C.Y. Lee and J.F. Abel,1978Shrivastava, R.K. and N.S.V. Kameswara Rao,2002Tsai, P.H.,2007Woods, R.D.,1967Woods, R.D.,1968Woods, R.D., N.E. Barnett and R. Sagesser,1974Wolf, J.P.,1994