Impact of highly weathered geology on pipe-jacking forces

View/ Open
File version
Version of Record (VoR)
Author(s)
Choo, Chung Siung
Ong, Dominic EK Leong
Griffith University Author(s)
Year published
2017
Metadata
Show full item recordAbstract
For the Kuching Wastewater Management System Phase 1 project in Kuching, Malaysia, 7·7 km of trunk sewer lines were constructed in the highly fractured, highly weathered Tuang Formation using a pipe-jacking method. The pipelines were founded at depths of up to 35 m below Kuching City, where the majority of the pipe-jacking activities would traverse the Tuang Formation. Jacking forces in highly fractured geology are not well understood as most jacking force models were derived for drives traversing soils. Therefore, a novel method was developed, whereby equivalent rock strength characteristics were interpreted from direct ...
View more >For the Kuching Wastewater Management System Phase 1 project in Kuching, Malaysia, 7·7 km of trunk sewer lines were constructed in the highly fractured, highly weathered Tuang Formation using a pipe-jacking method. The pipelines were founded at depths of up to 35 m below Kuching City, where the majority of the pipe-jacking activities would traverse the Tuang Formation. Jacking forces in highly fractured geology are not well understood as most jacking force models were derived for drives traversing soils. Therefore, a novel method was developed, whereby equivalent rock strength characteristics were interpreted from direct shear testing on reconstituted tunnelling rock spoils. Tangential peak strength parameters, c′t,p and ϕ′t,p , were developed from the nonlinear behaviour of the reconstituted spoils and applied to a well-established jacking model to assess arching and development of jacking forces from four documented drives. The back-analysed parameters μ avg and σ EV were used to demonstrate that geology had significantly affected the development of jacking forces. The back-analysis of the studied drives was successfully validated through finite-element modelling. This research shows that the developed parameters c′t,p and ϕ′t,p and the back-analysed parameters μ avg and σ EV can be reliably used to predict jacking forces in highly fractured, highly weathered geology.
View less >
View more >For the Kuching Wastewater Management System Phase 1 project in Kuching, Malaysia, 7·7 km of trunk sewer lines were constructed in the highly fractured, highly weathered Tuang Formation using a pipe-jacking method. The pipelines were founded at depths of up to 35 m below Kuching City, where the majority of the pipe-jacking activities would traverse the Tuang Formation. Jacking forces in highly fractured geology are not well understood as most jacking force models were derived for drives traversing soils. Therefore, a novel method was developed, whereby equivalent rock strength characteristics were interpreted from direct shear testing on reconstituted tunnelling rock spoils. Tangential peak strength parameters, c′t,p and ϕ′t,p , were developed from the nonlinear behaviour of the reconstituted spoils and applied to a well-established jacking model to assess arching and development of jacking forces from four documented drives. The back-analysed parameters μ avg and σ EV were used to demonstrate that geology had significantly affected the development of jacking forces. The back-analysis of the studied drives was successfully validated through finite-element modelling. This research shows that the developed parameters c′t,p and ϕ′t,p and the back-analysed parameters μ avg and σ EV can be reliably used to predict jacking forces in highly fractured, highly weathered geology.
View less >
Journal Title
Geotechnical Research
Volume
4
Issue
2
Copyright Statement
© 2017 Published with permission by the ICE under the CC BY-NC-ND 4.0 License (http://creativecommons.org/licenses/by-nc-nd/4.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, providing that the work is properly cited. You may not alter, transform, or build upon this work.
Subject
Civil geotechnical engineering