Skip to main content
CalcPro

NGI Q-System (Barton) Rock Tunnel Quality Index & Support Pressure Calculator

Easily calculate and compute ngi q-system (barton) rock tunnel quality index & support pressure calculator with accurate equations, live formulas, and expert guidance.

Percentage of intact drill core pieces > 10 cm.

Massive = 0.5-1; One joint set = 2; Two sets = 4; Three sets = 9; Crushed = 20.

Rough stepped = 3; Smooth undulating = 2; Slickensided planar = 0.5.

Unaltered = 0.75-1; Clay coated = 2-4; Heavy gouge = 6-12.

Dry = 1.0; Medium inflow = 0.66; Large pressure inflow = 0.2.

Medium stress = 1.0; High rock burst / squeezing stress = 5-20.

Calculated Result
10.67 index

Q-Value

Q-Value

10.67 index

Tunnel Quality Index Q

10.67

Estimated Roof Support Pressure Bar

0.45

Block Structure Quotient Rqd Over Jn

13.3

Inter Block Shear Quotient Jr Over Ja

2

10.67 — index

Calculation Breakdown

  1. Applied FormulaComputes the Norwegian Geotechnical Institute (NGI) Q-system rock quality index to select permanent rockbolt spacing, shotcrete lining thickness, and support pressure for civil tunnels.Q = \left(\frac{\text{RQD}}{J_n}\right) \left(\frac{J_r}{J_a}\right) \left(\frac{J_w}{\text{SRF}}\right)

Barton Q-System Tunnel Quality Metric Output

Interactive visualization based on your current inputs

Calculated Value
0.02.75.38.011Q-Value

What Is the NGI Q-System (Barton) Rock Tunnel Quality Index & Support Pressure Calculator?

This tool computes ngi q-system (barton) rock tunnel quality index & support pressure calculator with high precision arithmetic.

How Does the NGI Q-System (Barton) Rock Tunnel Quality Index & Support Pressure Calculator Work?

Computes the Norwegian Geotechnical Institute (NGI) Q-system rock quality index to select permanent rockbolt spacing, shotcrete lining thickness, and support pressure for civil tunnels.

NGI Q-System (Barton) Rock Tunnel Quality Index & Support Pressure Calculator Formula & Variables

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

Q=(RQDJn)(JrJa)(JwSRF)Q = \left(\frac{\text{RQD}}{J_n}\right) \left(\frac{J_r}{J_a}\right) \left(\frac{J_w}{\text{SRF}}\right)

Computes the Norwegian Geotechnical Institute (NGI) Q-system rock quality index to select permanent rockbolt spacing, shotcrete lining thickness, and support pressure for civil tunnels.

How to Use the NGI Q-System (Barton) Rock Tunnel Quality Index & Support Pressure Calculator

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

Step-by-Step Example Calculation

NGI Q-System (Barton) Rock Tunnel Quality Index & Support Pressure Calculator Example

Input Values:

rockQualityDesignationRqd:80
jointSetNumberJn:6
jointRoughnessNumberJr:2
jointAlterationNumberJa:1
jointWaterReductionJw:1
stressReductionFactorSrf:2.5
Worked Steps: Sample evaluation based on standard reference conditions.

Understanding Your Result

The calculated primary figure indicates the optimal or required index.

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.

\n

Related Calculators

Explore more tools and calculators in Construction Calculators

Length Converter

Convert length and distance between metric and imperial units including meters, feet, inches, kilometers, miles, and yards with exact SI definitions.

Percentage Calculator

Calculate percentages: what % X is of Y, P% of X, % change, discount price, and percentage points.

Temperature Converter

Convert temperatures between Celsius (°C), Fahrenheit (°F), Kelvin (K), and Rankine (°R) with step-by-step thermodynamic formulas.

Rankine Lateral Earth Pressure (Active & Passive) Calculator

Calculates Rankine active and passive lateral earth pressure coefficients, resultant thrust forces, and overturning moments on retaining walls.

Terzaghi Shallow Foundation Bearing Capacity Calculator

Calculates ultimate and allowable bearing capacity for shallow continuous strip and square footings using Terzaghi theory.

Culmann Slope Stability Planar Wedge Calculator

Evaluates critical slope failure height, planar sliding wedge angle, and safety factor against embankment landslides using Culmann method.