POINT
LOAD TEST FRAME
Background
Designed and marketed by Geotechnical Systems Australia P/L, the Point
Load Tester is a portable instrument used for the evaluation of the strength of rock
specimens. This test can measure the Point Load Strength (Is) and the Strength
Anisotropy Index (Ia) which is the ratio of Point Load Strength in the directions which
give the greatest and least values.
Diametrical and axial tests are performed on core samples, while block and irregular lump
tests may be done on prepared and unprepared samples respectively. The specimen is
fractured by applying load through a pair of uniaxial, conical platens.
If necessary, size corrections may be applied to core specimens to yield the standard
Is(50) value for a 50mm diameter core. Correlations between Is(50) values and the
Unconfined Compressive Strength are documented elsewhere in open literature.
Description
The instrument is based on a two column
anodised aluminium and stainless steel loading frame to minimise size and weight yet
maintain stiffness and load capacity.
Load is applied through a hand operated hydraulic jack mounted on the lower reaction
plate. The travel of the bottom platen is guided by close tolerance bushes on the guide
shafts while platen separation is measured by a sliding scale with an adjustable datum.
The platen points contain hardened steel balls to provide a true 5mm radius.
Applied load is measured via a strain-gauged upper point and displayed on an intelligent
liquid crystal display. This display also allows the operator to select the Point
Load Tester functions through its front panel keys. Alternatively a computer can run
a custom software package to record test data. Peak test values are shown on both
the local display and the computer monitor.
A battery life of at least fifteen hours ensures prolonged field or laboratory testing and
the frame can be run with mains power connected if available. A transparent safety
screen protects the operator from rock fragments during the test. The testing frame
can be used by holding the lifting handle while loading the sample however it should be
anchored to a suitable mounting base with the tapped holes below the base of the jack.
HOLLOW LOAD
CELLS
Manufactured for CADEANCO by Rock Technology P/L, the hollow load cell enables
direct measurement of axial loads in both conventional bolts and cable strand roof
support members. The integral spherical set minimises errors induced by axial
loading and gives reliable measurement over a range of collar conditions.
DISPLACEMENT
MEASUREMENT SYSTEMS
Many laboratory applications require the
evaluation of sample deformation under varying load conditions.
CADEANCO can design and manufacture a custom
measurement system for your application. Our basic designs employ both strain gauge
transducers and commercial linear potentiometer and LVDT sensors for the measurement of
diametrical, circumferential and axial strain in samples. These sensors can be
linked to a purpose built signal conditioning and readout to provide sensor data
output in almost any specified format.
We are happy to discuss and advise on your
application and follow the project through the design, manufacturing, installation and
commissioning stages to provide a turn-key solution to your problem. |
