Characterization of Internal Insertion Pressure During Installation of Fully Grouted Bolts

Details

• Personal Author:
  Cotten S ; Farrand J ; Giraldo L
• Description:
  The installation procedure of fully grouted rebar bolts requires that the bolt be pushed through the resin grout until it is fully inserted in the borehole. Resin grout is a highly viscous fluid that is forced to flow through the annulus between the bolt and the borehole as the bolt advances. Variables such as bolt insertion speed, bolt vs. borehole diameter and grout viscosity determine the magnitude of the pressure generated ahead of the bolt tip. Under weak rock conditions, the magnitude of the pressure of bolt insertion is often sufficient to initiate hydraulic fracturing along joints or bedding planes that allow injection of grout into the strata leading to significant loss of bolt encapsulation. The grout pressure front has also been linked to gloving, a bolt installation problem that reduces bolt effectiveness. A series of tests were conducted to characterize the pressure of bolt insertion during bolt installation under various conditions. Analysis of the data shows three distinct stages of pressure build up during bolt installation. Understanding of the mechanisms involved may allow development of strategies for controlling the pressure buildup and its negative impact during roof bolting under weak rock conditions. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Construction Industry Construction Materials Mining Occupational Health Safety
• Keywords:
  Coal Mining Construction Materials Ground Control Ground Stability Mine Shafts Mining Industry Rock Drillers Rock Mechanics Roof Bolts Underground Mining
• ISBN:
  0939084569
• Publisher:
  West Virginia University
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Proceedings
• Place as Subject:
  OSHA Region 3 ; Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  395-399
• NIOSHTIC Number:
  nn:20053060
• Citation:
  Proceedings of the 25th International Conference on Ground Control in Mining, August 1-3, 2006, Morgantown, West Virginia. Peng SS, Mark C, Finfinger GL, Tadolini S, Khair AW, Heasley KA, Luo Y, eds. Morgantown, WV: West Virginia University, 2006 Aug; :395-399
• Editor(s):
  Peng SS; Mark C; Finfinger GL; Tadolini SC; Khair AW; Heasley KA; Luo Y
• Federal Fiscal Year:
  2006
• Performing Organization:
  Raytheon Utd, Inc.
• Peer Reviewed:
  False
• Start Date:
  20020930
• Source Full Name:
  Proceedings of the 25th International Conference on Ground Control in Mining, August 1-3, 2006, Morgantown, West Virginia
• End Date:
  20060929
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:b575775adbd0aad1734302d6dff3d4fa026c5c324e4f1a5f1965c2b88a84b4af792c36b051a69d0ca4a5194e11fb25d88315c6e816e3c1966e348a3df1018e0a
• Download URL:
  https://stacks.cdc.gov/view/cdc/215910/cdc_215910_DS1.pdf
• File Type:
  [PDF - 145.16 KB ]