Hard Rock Tunneling

The Earth Mechanics Institute (EMI) at the Colorado School of Mines (CSM) has been performing basic and applied research and engineering for all types of excavation systems for more than 30 years. The body of knowledge acquired over this time period has allowed EMI to develop methods, which have been verified by field data, to analyze the performance of tunnel boring machines (TBMs) for hard rock tunneling. 

Current testing, design, and engineering programs for hard rock tunneling:

  Physical Property Testing

  Borehole Evaluation/Analysis

  Rock Mass Classifications

  Full Scale Cutter and Cutterhead Laboratory Testing for preferred cutter selection, optimum cutting geometry and machine specifications (thrust and power)

  Selection of Machine Type

 Cutterhead Layout and Balancing for Production Optimization evaluated by proven computer models

  Performance Predictions for penetration rates, system utilization, advance rates

 Cutter Cost Estimates

  Overall Project Costs and Completion Schedules

Standard Physical Property Tests for Hard Rock Tunneling:

Unconfined Compressive Strength (UCS) Test

Brazilian Tensile Strength (BTS) Test

Cerchar Abrasivity Index (CAI) Test

Punch Penetration Index (PI) Test

Thin Section Petrographic Analysis

Point Load Index (PL) Test

Acoustic Velocities and Dynamic Elastic Constants

Elastic Constants (Elastic Modulus and Poission's Ratio) 

Field Data Collection and Machine Data Logger Analysis for Hard Rock Tunneling:

Most of the today’s modern TBM have a PLC system, which is an on-board data acquisition system in order to record all the machine parameters. The type and amount of data needs to be recorded depends on machine type and ground conditions.  This type of information is very vital how to define the behavior and performance of the machine in varying rock conditions. EMI analyzes machine data logger from various TBM project by using customized Excel macro programs developed at the Institute.

More info on data logger analysis click this

Hard Rock Tunneling Projects:

These are some of the selected hard rock TBM projects that EMI got involved in different phases of each project.

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