Civil Engineering Project Management (4th Edition)

214 Civil Engineering Project Management
or may need to reject dayworks rates as a means of payment unless work has
been instructed on that basis.
17.8 Clause 12 claims for unforeseen conditions
Among the more difficult and therefore more challenging types of claim are
those relating to ‘unforeseen conditions’ – usually ground conditions. Clause 12
of the ICE conditions permits a contractor to claim extra payment:
if the contractor encounters physical conditions (other than weather conditions or
conditions due to weather conditions) or artificial obstructions which conditions or
obstructions could not in his opinion reasonably have been foreseen by an experienced
contractor.
There has frequently been criticism of this Clause 12 definition, but it has
stood the test of many contracts over the years, and no alternative phrase has
ever been put forward that works distinctly better. Some employers have tried
deleting the provisions of Clause 12 entirely; but the contractor then adds a
premium to his prices for the added risk he takes, so the employer pays this
whether or not any unforeseen conditions arise. A point to be borne in mind if
Clause 12 is deleted, is that it is usually impracticable to allow each tenderer to
conduct his own site investigations, so he has no way of limiting his risk other
than by raising his price. On a pipeline, for instance, the road authorities and
private landowners would not permit each tenderer to sink his own test borings
all along the route; nor may the employer allow each tenderer to sink test
borings on the site of some proposed works.
A different attempt to avoid the problem of unforeseeable ground conditions
is to specify the nature of the ground to be excavated as inclusive of practically
everything, for example, in soft or hard material including gravel, cobbles, boulders,
rock or concrete, running sand, etc. But if Clause 12 is left in the contract it
over-rides such a specification because the extent to which any of these materials
occurs remains undefined, so ‘unforeseeable conditions’ could still occur.
Although there is plenty of scope for the contractor to claim that things have
not turned out as he expected, the criterion is whether ‘an experienced contractor’
could have foreseen the ‘event’ or not. To decide this with respect to ground
conditions depends on the geotechnical information made available to tenderers
together with any information readily available, such as that relating to
the geology and soils of the area, and common experience locally. It needs to be
remembered that when the contractor undertakes the obligation to construct
the works he should have looked into these matters. Often it is not so much the
event as such which is unforeseen, but its magnitude.
For example, test borings may show that hard bands of siltstone are likely
to be encountered in tunnelling. But if, instead of occasionally appearing in the
tunnel face and disappearing, a band manages to stay exactly in the soffit of the
tunnel for a considerable length – this has occurred – this greatly adds to driving