Economical Benefits of Rock Joint Testing


Despite the common belief that joint surface properties control the behavior of the rock mass and ultimately the excavated structure, 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 begin to 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 offer a starting point on discussions for further study.

Meeting Name

GeoCongress: State of the Art and Practice in Geotechnical Engineering (2012: Mar. 25-29, Oakland, CA)


Geosciences and Geological and Petroleum Engineering

Second Department

Mining Engineering

Keywords and Phrases

Degree Of Weatherings; Economical Benefits; Friction Angles; Joint Property; Mechanical Parameters; Rock Tunnel; Sensitivity Curves; Support Method; Geotechnical Engineering; Investments; Safety Factor; Weathering; Tunnels

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version


File Type





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

Publication Date

01 Mar 2012