Location
Arlington, Virginia
Date
15 Aug 2008, 11:00am - 12:30pm
Abstract
A case history of extensive 60-m high excavations in a weak rock mass for a canyon landfill in Northern California is presented. The landfill is underlain by the Panoche Formation, a complex series of sandstones, siltstones, claystones, shales and conglomerates, thought to be dominantly turbidites, deposited as sub-sea fan deposits. As part of the design, kinematic analyses were performed, accompanied by two independent approaches used to evaluate the strength of the rock mass. One approach was based on laboratory rock core testing, while the second approach was based on the Hoek and Brown Criterion using mostly field observations. The two approaches yielded consistent results. Characterization of the rock mass indicated a pronounced improvement in the rock structure and the condition of the discontinuities with depth, resulting in an increasing Geologic Strength Index (GSI) with depth. Subsequent analyses performed using a layered Hoek and Brown Criterion allowed further steepening of rock excavations. Comparisons are also made in the results of the analyses using a layered vs. a more commonly used uniform Hoek and Brown approach. It was observed that the layered approach identified more critical, relatively shallow failure surfaces and eliminated the spurious apparently critical deep-seated rock mass failure surfaces, generated assuming a uniform rock mass.
Department(s)
Civil, Architectural and Environmental Engineering
Meeting Name
6th Conference of the International Conference on Case Histories in Geotechnical Engineering
Publisher
Missouri University of Science and Technology
Document Version
Final Version
Rights
© 2008 Missouri University of Science and Technology, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Zekkos, Dimitrios; Cohen-Waeber, Julien; Medley, Edmund; Hunt, Chris; and Jesionek, Krzysztof, "Characterization of a Weak Rock Mass and Geoengineering Analyses for a Canyon Landfill in Northern California" (2008). International Conference on Case Histories in Geotechnical Engineering. 5.
https://scholarsmine.mst.edu/icchge/6icchge/session06/5
Characterization of a Weak Rock Mass and Geoengineering Analyses for a Canyon Landfill in Northern California
Arlington, Virginia
A case history of extensive 60-m high excavations in a weak rock mass for a canyon landfill in Northern California is presented. The landfill is underlain by the Panoche Formation, a complex series of sandstones, siltstones, claystones, shales and conglomerates, thought to be dominantly turbidites, deposited as sub-sea fan deposits. As part of the design, kinematic analyses were performed, accompanied by two independent approaches used to evaluate the strength of the rock mass. One approach was based on laboratory rock core testing, while the second approach was based on the Hoek and Brown Criterion using mostly field observations. The two approaches yielded consistent results. Characterization of the rock mass indicated a pronounced improvement in the rock structure and the condition of the discontinuities with depth, resulting in an increasing Geologic Strength Index (GSI) with depth. Subsequent analyses performed using a layered Hoek and Brown Criterion allowed further steepening of rock excavations. Comparisons are also made in the results of the analyses using a layered vs. a more commonly used uniform Hoek and Brown approach. It was observed that the layered approach identified more critical, relatively shallow failure surfaces and eliminated the spurious apparently critical deep-seated rock mass failure surfaces, generated assuming a uniform rock mass.
