This paper deals with the elastic-plastic analysis of fibre-reinforced
soil that is treated as a macroscopically homogeneous composite mater
ial. First, the theory of such a material is briefly described. The th
eory allows for straightforward determination of the initial yield sur
face of reinforced soil. The initial yield surface is defined as a sur
face, in the macrostress space, on which either the soil or the reinfo
rcement first becomes plastic the second constituent being in. an elas
tic state. Further loading of the composite causes the regrouping of m
icrostresses in both constituents up to the stage at which the second
constituent becomes plastic. The points corresponding to such states f
orm, in the macrostress space, the global yield surface for reinforced
soil. The global yield surface can be determined analytically only in
special cases. In a general case it can be determined by numerical in
tegration of incremental equations describing an elasto-plastic range
of the composite's behaviour. The global yield surface is determined f
or various sets of initial data. The results are compared with the lim
it surface defined by the rigid-plastic model of reinforced soil. Conc
lusions of practical importance are drawn.