When performing lateral load tests on deep foundations, it is
desirable to obtain horizontal displacement versus depth
profiles. These profiles can be used in conjunction with lateral
load versus displacement curves to calibrate lateral pile analysis
programs. In addition, the displacement versus depth curves
can be used to determine bending moment versus depth profiles.
Horizontal displacement versus depth profiles have typically
been determined using inclinometer probes or strings of
downhole inclinometers. Inclinometer probes require the user
to measure slope at 0.6 m intervals within a special grooved
pipe which is typically concreted into place within the pile. The
displacement of the pile must be held constant over a 15 to 20
minute period while the inclinometer measurements are made.
Strings of down hole inclinometers can also be installed at
various intervals within the inclinometer pipe. This option is
more expensive but allows measurements to be obtained
simultaneously and more quickly. Nevertheless, the
displacement of the foundation must be held relatively constant
for a several seconds so that the inclinometers can stabilize and
provide an accurate reading. This requirement usually
precludes their use for dynamic applications.
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