Basal Reinforcement

The stability of an embankment constructed on soft soil is governed mostly by the shearing resistance of the foundation, and the construction of an embankment on soft soil may be limited to a problem of bearing capacity. Reinforcement may be placed at foundation level to prevent shear failure both in the embankment fill and in the foundation soil, any reduction in differential settlement is of secondary importance. It is important to consider that the stability of an embankment on soft soil is most critical during construction, because the relatively low permeability of the soft foundation does not permit full consolidation in the normal time scale of construction. At the end of construction the embankment loading has been applied, but the gain in shearing resistance of the foundation due to consolidation might be insufficient for stability. It should be noted that, these problems can be compounded by quicker/shorter construction periods. Once consolidation has occurred, the resulting improvement in shearing resistance in the foundation should usually remove the need for the reinforcement to improve stability. Thus during the period between the end of construction and consolidation of the foundation, the fundamental strength requirement of the reinforcement should be that at any instant in time the factored reinforcement design strength equals or exceeds the design load. Basal reinforcement stabilizes an embankment over soft ground by preventing lateral spreading of the fill, extrusion of the foundation and overall rotational failure. This stabilizing force is generated in the reinforcement by shear stresses transmitted from the foundation soil and fill which place the reinforcement in tension.

 Features and Applications

• Differential settlement can be controlled by the construction of a basal platform to spread the loading upon the ground
• Absorb, spread, span or dissipate the applied loads vertically downwards into the ground, or into the piles.