For many rock types, Mohr-Coulomb (MC) failure criterion is a reasonable approximation to strength data, featuring a linear relation with two principal stresses and two material parameters that describe a stress intercept (e.g. uniaxial compression or uniform triaxial tension) and pressure sensitivity (e.g. internal friction angle φ). A criticism of MC is the absence of the intermediate principal stress. Paul-Mohr-Coulomb (PMC) criterion removes that limitation by including three principal stresses. PMC has the advantage over other multi-axial stress criteria in that three material constants, such as one stress intercept and two friction angles, one for compression φc and one for extension φe, are readily identified. PMC failure criterion is reviewed and data from a series of conventional triaxial compression and extension experiments on Indiana limestone are analyzed. The extension friction angle is larger than the compression friction angle, a sufficient but not necessary condition of the intermediate stress effect. To capture the behavior of the rock in multi-axial loading, PMC is extended to include the results of plane strain compression experiments through the construction of two planes with six parameters.
|Original language||English (US)|
|Title of host publication||50th US Rock Mechanics / Geomechanics Symposium 2016|
|Publisher||American Rock Mechanics Association (ARMA)|
|Number of pages||5|
|State||Published - 2016|
|Event||50th US Rock Mechanics / Geomechanics Symposium 2016 - Houston, United States|
Duration: Jun 26 2016 → Jun 29 2016
|Name||50th US Rock Mechanics / Geomechanics Symposium 2016|
|Other||50th US Rock Mechanics / Geomechanics Symposium 2016|
|Period||6/26/16 → 6/29/16|
Bibliographical noteFunding Information:
Partial support was provided by the DOE Grant DE-FE0002020 and the UMN Undergraduate Research Opportunities Program (UROP). J. Meyer assisted with experimental design.
Copyright 2016 ARMA, American Rock Mechanics Association.