The standard apparatus consists of the following:
A gearbox-driven horizontal screw ram and geared jack upon a rigid
stand and horizontal base. The gearbox and motor are used with the
stepless speed control box.
The control box is situated on the front, to the left of the metal stand.
To avoid the need of calibration charts and to maximize the ease
of desired speed selection, the speed control of the apparatus is
calibrated in inch/min (engineering units), which are indicated digitally.
The main base also incorporates a vertical support bracket, to guide
the spindle of the selected means of reactive measurement of the
applied shear force. (force indicators H -4454.XXX are not included
and must be selected from the Humboldt Mfg. Co. range). There is a
reaction bracket at the rear of the base, against which the load ring or
measurement device is pushed.
The shearboxes are equipped with a carriage mounted on linear ball
races resting upon sliding tracks. When mounted, the carriage is
transversely restrained but is free to glide axially along the centerline
of the geared jack and reaction bracket. Affixed to the geared jack is
the vertically mobile dial gauge arm. The dial gauge arm mounts an
anti -clockwise dial gauge allowing for direct visual measurement of the
consolidation of the sample.
Shearbox squares are not included with the standard apparatus,
though can be purchased separately as an accessory.
The method of normal stress application, on the standard apparatus,
is by a vertical load hanger resting above the soil specimen and
hanging downwards permitting the selected weights to rest upon its
load mount, while traveling with the upper specimen half, (should any
lateral movement take place). The consolidation force is applied to the
specimen proportionally by the amount of weights placed upon the
hanger mount.
The load ring and dial gauges are necessary to perform the shear
testing procedure and are supplied as extras. The shear force is
obtained by the geared jack moving along the axis of the base in an
attempt to move the carriage and the slightly separated halves of
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