Development of New Three-Dimensional Rock Mass Strength Criteria

Details

• Personal Author:
  He M ; Kulatilake PHSW ; Mehranpour MH ; Xingen M
• Description:
  Two new three-dimensional rock mass strength criteria are developed in this paper by extending an existing rock mass strength criterion. These criteria incorporate the effects of the intermediate principal stress, minimum principal stress and the anisotropy resulting from these stresses acting on the fracture system. In addition, these criteria have the capability of capturing the anisotropic and scale dependent behavior of the jointed rock mass strength by incorporating the effect of fracture geometry through the fracture tensor components. The new criteria are proposed after analyzing 284 numerical modeling results of the polyaxial, triaxial and biaxial compression tests conducted on the jointed rock blocks having one or two joint sets by the PFC3D software. Some of these simulation results were compared with experimental results to validate the developed PFC3D model that was used for numerical modeling of jointed blocks. In this research to have several samples with the same properties a synthetic rock material that is made out of a mixture of gypsum, sand and water was used. Altogether, 12 joint systems were chosen; some of them had one joint set and the rest had two joint sets. Joint sets have different dip angles varying from 15 degrees to 45 degrees at an interval of 15 degrees with dip directions of 30 degrees and 75 degrees for the two joint sets. Each joint set also has three persistent joints with the joint spacing of 42 mm in a cubic sample of size 160 mm. The minimum and intermediate principal stress combination values were chosen based on the uniaxial compressive strength (UCS) value of the modeled intact synthetic rock. The minimum principal stress values were chosen as 0, 0.2, 0.4 and 0.6 of the UCS. For each minimum principal stress value, the intermediate principal stress value varies starting at the minimum principal stress value and increasing at an interval of 0.2 of the UCS until it is slightly lower than the strength of the sample under the biaxial loading condition with the same minimum principal stress value. To express the new rock mass strength criteria, it was also necessary to determine the intact rock strengths under the same confining stress combinations mentioned earlier. Therefore, the intact rock was also modeled for all three compression tests and the intact rock strengths were found for 33 different minimum and intermediate principal stress combinations. [Description provided by NIOSH]
• Subjects:
  Geology Occupational Health Safety
• Keywords:
  Anisotropy Author Keywords: Discrete Element Method DEM Fracture Tensor Geologic Formations Geotechnical Engineering Intermediate Principal Stress Particle Flow Code PFC Polyaxial Compression Test Rock Mass Strength Rock Mechanics

  More +
• ISSN:
  0723-2632
• Document Type:
  Text
• Funding:
  Contract
• Genre:
  Journal Article
• Place as Subject:
  Arizona ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  51
• Issue:
  11
• NIOSHTIC Number:
  nn:20068872
• Citation:
  Rock Mech Rock Eng 2018 Nov; 51(11):3537-3561
• Contact Point Address:
  Pinnaduwa H. S. W. Kulatilake, Rock Mass Modeling and Computational Rock Mechanics Laboratories, University of Arizona, Tucson, AZ, 85721, USA
• Email:
  kulatila@u.arizona.edu
• Federal Fiscal Year:
  2019
• Performing Organization:
  University of Arizona
• Peer Reviewed:
  True
• Start Date:
  20110901
• Source Full Name:
  Rock Mechanics and Rock Engineering
• End Date:
  20160831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:275adc0c98e8364a2e43cefdd3ce860c9fd214c6ff84ea2b5be84ad1589c299d7708a8b300acd7a2c09e81abd2b82425390cc11cc993816fe8b8aed60d61c600
• Download URL:
  https://stacks.cdc.gov/view/cdc/207439/cdc_207439_DS1.pdf
• File Type:
  [PDF - 6.76 MB ]