(DC) is well made. However, Schmertmann (1985), Lucas As indicated by Schmertmann (1985) and others, it appears (1986), and others have shown experimentally that DC has that sand may become overcollsolidated after DC. It is, howrelatively greater effect on vertical stresses than on the stress ever, yet to be established experimentally and (or) analytistate in the horizontal direction. Significant increase in horcally what are the relationships between DC parameters and izontal stresses due to DC is generally confined to an affected sand overconsolidation and to show that such overconsoliarea at a depth of up to four times the tamper width. dation may result in reduction of the required DC energy Heh (1991) shows that stress profiles must be signifito achieve specified density or other design property to the cantly different before and after compaction. This was also required design depth DI. It will be especially interesting established from computational s tudies by Poran and to st i~dy the relationship between DI requirements and overRodriguez (1993). In his discussion, Ghaly also comments consolidation ratio so that settlement and bearing capacity that reflection waves from tank walls and rebound from the design criteria be met. bottom coitld have considerable effects on lateral and vertical stress states in the sand mass. In recognition of such conHeh, K.S. 1991. Dynamic compaction of sand. Ph.D. dissertation, ditions, Heh (1991) placed pressure transducers in both verPolytechnic University, Brooklyn, N.Y. tical and horizontal directions to monitor these effects in Lucas, R.G. 1986. Dynamic compaction for highway construction. his DC model tests. H~ reported that reflectionIII Design and construction guidelines. Vol. 1. Federal Highway wave effects were negl igible w i t h t he selected test Administration Report No. RD-861133, Washington, D.C., pp. 204-2 19. configurations. Schmerttnann, J.H. 1985. Measure and use of the in-situ lateral Heh (L991) 'lso gave inforlnation about the posistress. In Proceedings of the Osterberg Sylllposium on the tions and readings of the pressure transducers in his 12 tests practice of ~ ~ ~ ~ d ~ ~ i ~ ~ ~ ~ ~ i ~ ~ ~ ~ i ~ ~ , ~~~h~~~~ ~~ university, where he used three vertically oriented pressure transducEvanston, [I[., pp, 189-213. ers embedded at different depths in the sand underneath the Poran, C.J., and Rodriguez, J.A. 1993. Finite element analysis of center of the DC tamper. impact behavior of sand. Soils and Foundations, 32: 68-80.