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Lab Services: Rock testing

Lab Services: Rock testing

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Test Method Title

Punch Penetration Index

Reference Number

Handewith

Material

Rock

Test Property

Punch Penetration Index

Description of Test

The punch test is a nonstandard laboratory test that was originally designed to provide a direct method for estimating the normal loads on button and disc cutters during mechanical excavation of rock. It has been used as a tool for estimating Tunnel Boring Machine penetration rates. The test has been also used to evaluate certain rock characteristics such as brittleness, bedding or cleavage, and porosity. A tungsten carbide indenter is pressed into a saw cut rock sample that is confined by a steel ring. During the test the rock fails by crushing and chipping. The load on the indenter and its depth are recorded to produce a plot of force versus penetration.

Preferred Test Sample Size

Number of Test Specimens

1

Test Specimen Size

A minimum of 4 in of core

Keywords

Punch Penetration, Tunnel Boring Machines, Penetration Rates

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