Work Item
ASTM WK74923
New Test Method for Determining Rock Shear Strength in a Borehole with a Borehole Shear Device
1. Scope
A rock borehole shear test for rapid in situ measurements and reporting of the cohesion and friction angle of weak to strong, weathered to fresh rocks, including coal, using a 76-mm diameter borehole (NX-size) oriented in any direction. To reduce the bias in the results caused by testing only suitable rock cores recovered at the drill hole and biased further after transporting and sample preparation at the testing laboratory at some moisture content and stress level that is probably significantly different than in situ.
Keywords
creep limit; in situ tests; limit pressure; modulus; stress-strain; in-situ testing; rock pressuremeter; dilatometer; deformation modulus; back analysis; in situ stress; hysteresis
Rationale
The test addresses the needed and advantages of rapidly obtaining data and the ability to test rocks that are too weak or fractured to sample by core or other methods. The test reduces bias in the results caused by testing only surviving sections of rock cores at the drill hole and possibly biased even more after transporting and sample preparation at the testing laboratory at some moisture content and stress level probably significantly different than in situ. It can be used to obtain shear strength data for coal and non-coal mine pillars, rock slope mass, socketed piers in rock, and underground openings for designs, quality assurance, and rapid measurements. Users of the data will be rock bolt engineers, rock foundation engineers, slope stability engineers, tunneling and underground mining engineers, and rock pier engineers.
The title and scope are in draft form and are under development within this ASTM Committee.
Work Item Status
Date Initiated: 11-23-2020
Technical Contact: Jack Touseull
Item: 000
Ballot:
Status: