This tool estimates the stand up time of a cavern or mined tunnel in rock conditions, by Bieniawski's Empirical method using the rock mass rating or Q rating.
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About this calculator
Mined Tunnel Stability Estimator is a valuable tool for estimating the stand-up time of a cavern or mined tunnel under specific rock conditions. Using Bieniawski's Empirical method, it calculates stability based on the rock mass rating (RMR) or Q rating, providing a quick and effective assessment for stability planning in tunnel projects.
This calculator is for:
- Geotechnical Engineers – needing a reliable estimate for stand-up time to plan for safe excavation and support installation in varying rock conditions.
- Tunnel Designers – assessing the stability of mined tunnels to optimize tunnel geometry and rock reinforcement requirements.
- Construction Project Managers – conducting feasibility checks to anticipate support costs and timelines for different rock mass conditions.
This tool enables fast feasibility assessments, helping users understand stability concerns and potential time frames for unsupported rock conditions. Alternative approaches for estimating tunnel stability include using other empirical methods, advanced modeling software, or consulting reference texts like Rock Mass Classification: A Practical Approach in Civil Engineering by B. Singh and R.K. Goel and Engineering Rock Mass Classifications by Z.T. Bieniawski.
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Common calculators
Design guides
FAQs
What factors determine the stand-up time in mined tunnels?
Stand-up time is influenced by rock type, joint spacing, ground conditions, excavation size, and tunnel geometry, among other factors.
What are typical support types for mined tunnels in weak rock?
Support options include rock bolts, shotcrete, steel arches, and mesh reinforcement, chosen based on rock stability and load requirements.
How does excavation geometry impact tunnel stability?
Larger excavations or unusual geometries increase the risk of instability, requiring more robust support systems and higher RMR or Q ratings for safety.
Learn about the benefits of using CalcTree on engineering projects!
How to verify a calculation
Engineering calculations require clarity, precision, and professionalism. Here are some best practices we use at CalcTree:
- Technical Requirements: Start with boundary conditions, units, sign conventions, and design standards.
- Check the Math: Review the calculation step-by-step. Clarify unusual steps, compare results with hand calculations or tools, and test with multiple examples.
- Peer Review: Have an independent reviewer check for logic, accuracy, and compliance.
For more on verification, see CalcTree’s internal methods.
