SMALL DAMS

Chapter IV
Extent of inspection concerning compaction
Reliable inspection of compaction requires the constant presence of a competent
geotechnician whose judgement will be based on a number of PROCTOR tests. Since
this constant inspection is in addition to general works supervision, which is part of the
engineer's services in the case of a standard mission, it will mean an extra cost for the
owner. This gives rise to the following recommendations:
!" a competent representative of the engineer, with complete laboratory equipment,
should ensure constant inspection of compacting for all dams where H 2 V is greater
than 300;
!"when H 2 V is greater than 700, a laboratory technician (or more than one if the
rate of placement so requires) will back him up;
!"when H 2 V is less than 300, constant inspection is also recommendable but, if this
is not possible, the engineer should conduct a standard inspection of compaction
during each of his visits. He will also carry out global inspection of all the compacted
layers using a light dynamic penetrometer, which will in particular detect the presence
of soft materials.
The frequency of the measurements and tests will depend on construction site conditions;
recommendations for all dams are:
!" at least one measurement (w, d) per 1 000 m 3 of materials compacted;
!" one Proctor standard test for one to ten measurements (w, d).
The particular technical clauses (see p. 100 and 101) should stipulate what method
to follow in case of non compliance with specifications; in particular alarm points
should be defined concerning the suitability of materials (grading, water content)
and hold points for their placement (thickness of layers, density, water content).
107
Set of record drawing documents
This step is often neglected for the smallest structures, but grouping all the documents
concerning construction in an as-built file is very important to prepare and facilitate
maintenance. When this file is set up, special attention should be paid to all elements
that will no longer be accessible after construction (surveys of excavations, position of
the drainage system, fill inspection, type and layout of monitoring devices) as well the
description of any incidents that occurred during construction such as floods, frost, or
holds due to rain.