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Hoek-Brown Rock Mass Failure Criterion Calculator

Easily calculate and compute hoek-brown rock mass failure criterion calculator with accurate equations, live formulas, and expert guidance.

Uniaxial compressive strength of intact rock core specimen.

Surface structure and joint condition rating (e.g. 65 for blocky/good).

Lithology petrographic constant (e.g. 15 for sandstone, 25 for granite, 10 for basalt).

0 for undisturbed TBM tunnel, 0.7 to 1.0 for heavy open-pit production blasting.

Minor principal effective confining stress.

Calculated Result
75.2 MPa

Failure Stress (σ₁)

Failure Stress (σ₁)

75.2 MPa

Major Principal Strength Sigma1 M Pa

75.2

Rock Mass Unconfined Strength Sig Cm M Pa

13.5

Hoek Brown Parameter Mb

4.298

Hoek Brown Parameter S

0.02047

75.2 — MPa

Calculation Breakdown

  1. Applied FormulaCalculates non-linear failure envelopes, rock mass unconfined compressive strength, and triaxial shear capacity for jointed rock masses using the generalized Hoek-Brown (2002) criterion.\sigma_1' = \sigma_3' + \sigma_{ci} \left( m_b \frac{\sigma_3'}{\sigma_{ci}} + s \right)^a, \quad \sigma_{cm} = \sigma_{ci} s^a

Hoek-Brown Criterion Metric Output

Interactive visualization based on your current inputs

Calculated Value
0.019385675Failure Stress (σ₁)

What Is the Hoek-Brown Rock Mass Failure Criterion Calculator?

This tool computes hoek-brown rock mass failure criterion calculator with high precision arithmetic.

How Does the Hoek-Brown Rock Mass Failure Criterion Calculator Work?

Calculates non-linear failure envelopes, rock mass unconfined compressive strength, and triaxial shear capacity for jointed rock masses using the generalized Hoek-Brown (2002) criterion.

Hoek-Brown Rock Mass Failure Criterion Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

σ1′=σ3′+σci(mbσ3′σci+s)a,σcm=σcisa\sigma_1' = \sigma_3' + \sigma_{ci} \left( m_b \frac{\sigma_3'}{\sigma_{ci}} + s \right)^a, \quad \sigma_{cm} = \sigma_{ci} s^a

Calculates non-linear failure envelopes, rock mass unconfined compressive strength, and triaxial shear capacity for jointed rock masses using the generalized Hoek-Brown (2002) criterion.

How to Use the Hoek-Brown Rock Mass Failure Criterion Calculator

  1. Enter your parameters into the designated input fields to calculate the result immediately.

Step-by-Step Example Calculation

Hoek-Brown Rock Mass Failure Criterion Calculator Example

Input Values:

intactUniaxialCompressiveStrengthSigciMPa:95.0
geologicalStrengthIndexGsi:65.0
intactRockConstantMi:15.0
blastDisturbanceFactorD:0.0
minorPrincipalConfiningStressSigma3MPa:10.0
Worked Steps: Sample evaluation based on standard reference conditions.

Understanding Your Result

The calculated primary figure indicates the optimal or required MPa.

Factors That Affect the Result

  • Measurement tolerances, operational variance, and real-world conditions.

When Should You Use This Calculator?

  • Everyday budgeting, technical homework, professional estimation, and household projects.

Assumptions & Limitations

  • Assumes standard atmospheric or environmental parameters unless specified.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Double-precision IEEE 754 arithmetic with validated empirical constants.

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