Economical Benefits of Rock Joint Testing


Quantitative joint properties are typically unknown on most rock tunnel designs. To quantify joint properties in terms of cohesion, waviness, roughness, friction angle, degree of weathering, in filling, healed material and other mechanical parameters requires joint testing, which is typically a costly proposition. But sometimes this investment in testing leads to significant cost savings. This paper will review joint properties and their impact on tunnel and shaft stability and present a sensitivity analysis performed by using Unwedge to analyze the effects of each input on the required amount of support to establish a minimum target safety factor. Factors that will be analyzed include: tunnel size, tunnel shape and trend, ground support methods and cost, and joint properties. Sensitivity curves will be offered to determine if joint testing is economically beneficial to future projects.

Meeting Name

North American Tunneling Conference (2012: Jun. 24-27, Indianapolis, IN)


Geosciences and Geological and Petroleum Engineering

Second Department

Mining Engineering

Keywords and Phrases

Cost Saving; Economical Benefits; Friction Angles; Joint Property; Mechanical Parameters; Rock Joint; Rock Tunnel; Sensitivity Curves; Support Method; Investments; Mechanical Properties; Safety Factor; Weathering; Tunnels

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2012 American Society of Civil Engineers (ASCE), All rights reserved.

Publication Date

01 Jun 2012

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