You are being redirected because this document is part of your ASTM Compass® subscription.
    This document is part of your ASTM Compass® subscription.

    If you are an ASTM Compass Subscriber and this document is part of your subscription, you can access it for free at ASTM Compass

    Mechanism of Fracture of Hard Rock Using a Drag Bit Assisted by Waterjets

    Published: 01 January 1979

      Format Pages Price  
    PDF (244K) 9 $25   ADD TO CART
    Complete Source PDF (13M) 637 $60   ADD TO CART

    Cite this document

    X Add email address send
      .RIS For RefWorks, EndNote, ProCite, Reference Manager, Zoteo, and many others.   .DOCX For Microsoft Word


    It is shown that the mechanism of rock fracture is similar both when a blunt drag bit is used to cut strong rock and when a flat-bottomed punch is pressed into the rock surface. In order to study this fracture mechanism an experimental technique was developed which involved indenting the rock specimen in a quasi-static manner, using a drag bit as the punch. The effect of directing waterjets adjacent to the bit was investigated and it was found that these jets caused a rock chip to form with lower than normal forces applied to the bit. This finding agrees with results of previous experiments where lower forces were applied to the bit during the cutting operation when waterjets were used. A hypothesis is proposed to explain the action of the waterjets on the rock to produce this reduction in the indentation force.


    drag bits, waterjets, hard rock, cutting, indentation, rock fracture, erosion

    Author Information:

    Hood, M
    Assistant professor, University of California, Berkeley, Calif.

    Committee/Subcommittee: G02.10

    DOI: 10.1520/STP35817S