Parametric Studies on the Behaviour of Reinforced Soil Retaining

Axial force distribution in the reinforcement
Horizontal soil pressure acting at the back of the reinforced soil mass and the
vertical soil pressure at the base
Vertical soil stress on each reinforcement layer
Horizontal soil pressure acting at the face
Horizontal and vertical forces transferred to the wall face
Horizontal deformation of the reinforced soil mass
Effect of varying the design parameters (i.e. reinforcement stiffness, soil
properties, reinforcement spacing, surcharge condition, construction procedures,
etc.) on the response of the system
2.5.1 Vertical and Horizontal Soil Stress Distribution
Several types of vertical stress distribution patterns are assumed in the analysis and
design of reinforced soil mass. Uniform, trapezoidal, Meyerhof distributions and 2:1
stress dispersion method are typical examples. Maximum stress is attained within the
reinforced zone. Close to the far end of reinforced zone, the vertical soil stress
reaches a minimum. Further away into the unreinforced retained fill, the vertical soil
stress attains the minimal value. The vertical soil stress close to the facing depends
on the facing rigidity (Tatsuoka, 1992). Rigid facing decreases the vertical soil stress
close to the facing due to load transfer from the soil to the facing. Such effect of the
facing leads to higher reinforcement force and requires higher bearing capacity in the
design of foundations. Horizontal soil stress primarily depends on the number of
reinforcement layer, the stiffness and the creep of the reinforcement and the degree
of yielding of the wall face as shown in Fig. 2.9. Relative deformation of the wall
face and soil with the reinforcement results to increased transfer of horizontal stress
to reinforcement rather than to facing. The horizontal soil stress increases as the
number of reinforcement layers is increased. Rowe and Ho (1993) noted that there
are no literatures giving any real observed information on the horizontal soil stress
distribution further back into the reinforced soil.
17